EP2815130A2

EP2815130A2 - Diffusor, ventilator having such a diffusor, and device having such ventilators

Info

Publication number: EP2815130A2
Application number: EP13748807.8A
Authority: EP
Inventors: Michael Stephan; Friedrich LÖRCHER; Daniel SEIFRIED
Original assignee: Ziehl Abegg SE
Current assignee: Ziehl Abegg SE
Priority date: 2012-02-17
Filing date: 2013-02-15
Publication date: 2014-12-24
Anticipated expiration: 2033-02-15
Also published as: US10197070B2; DE102012003336A1; CN104302927A; RU2014137394A; ES2922729T3; SI2815130T1; WO2013120623A2; CN104302927B; US20150300372A1; WO2013120623A3; JP6357424B2; WO2013120623A8; JP2015508884A; EP2815130B1; RU2620308C2

Abstract

The invention relates to a diffusor having a wall (8) that encloses an inlet having a round cross-section that transitions into an angular cross-section on the outlet of the diffusor over the height of the wall (8) of the diffusor. The transitions (15) between the sides (34 to 37) of the wall (8) have a twist in the height direction that follows the twirl of the flow of air through the diffusor. The ventilator has such a diffusor. The device has a housing on which at least two ventilators, each having one diffusor, are arranged.

Description

Diffuser, fan with such a diffuser and device with such fans

The invention relates to a diffuser according to the preamble of claim 1 or 10 or 11 or 12 or 14 or 15, a fan according to the preamble of claim 21 or 23 or 24 and according to claims 25 to 30 and a Device with such fans according to claim 31 or 32.

Fig. 12 shows a prior art device according to the prior art (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 the entire dynamic energy is lost at the fan outlet.

In order to reduce the considerable flow losses at the outlet of pipelines, fans and the like, outlet diffusers are used (DE 20 201 1 004 708 U1, FR 27 28 028). On devices such as table coolers, however, there is only a limited amount of space in the radial direction. Since the outlet diffusers have a circular cross-section, the fans with the outlet diffusers can not be lined up close to each other. However, this is often required in such devices, the fans must also be arranged multi-row close together. Space is lost on a device with multiple fans. Between the diffusers then also form local dead water areas, which lead to increasing losses.

The invention has the object of providing the generic diffuser and the generic fan in such a way that the place on the equipment can be optimally utilized without the need for a structurally complex training is necessary.

This object is achieved in the generic diffuser according to the invention with the characterizing features of claim 1 or 10 or 1 1 or 12 or 14 or 15, the generic fan according to the invention with the characterizing features of claim 21 or 23 or 24 and according to the invention the claims 25 to 30 and the device with the features of claim 31 and 32 solved.

In the diffuser according to the invention according to claim 1, the transitions between the sides of the wall in the height direction, a twist which follows the swirl of the flow of air through the diffuser. The transitions thus do not run in the height direction of the diffuser wall along a straight line, but curved accordingly. The transition areas are designed to follow the flow direction of the air in the diffuser and the swirl of the flow behind the impeller of the fan. This results in minimal losses in the range of these transitions. The diffuser wall itself has an angular outline at least at the outlet, wherein an angular outline also means that the transition between the sides of the diffuser wall can be rounded. The angular design makes it possible to place several diffusers with only a small distance next to each other, so that in devices in which only a limited amount of space is available and several diffusers are needed, they 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, the connection region of which is generally round or circular. The diffuser according to the invention can therefore also be grown on existing fans.

The outlet of the diffuser wall has advantageously quadrangular outline, so that adjacent diffusers with their respective contour sides either abutting one another or with only the smallest distance next to and behind each other can be positioned. As a result, the surface is optimally used to delay the flow velocity.

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

Optimal training results when the diffuser wall has an angular outline over most of its height. Secondary and / or successive diffusers can then be arranged with the shortest distance or even abutting. As a result, an almost complete use of the corresponding device surface is possible.

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

The cross-section of the diffuser increases in a preferred embodiment in the flow direction, which is advantageous for the reduction of the flow velocity. It is advantageous if the cross section of the diffuser initially decreases from the inlet end and then increases. The flow can thereby be delayed with only small losses in the increasing cross-sectional area, resulting in a high diffuser efficiency.

Advantageously, the diffuser is provided with at least one further wall, which is surrounded by the diffuser wall at a distance. This additional wall results in optimum flow conditions.

The walls of the diffuser can in this case have the same height, but also have different heights. It is therefore very easy to achieve the desired flow conditions by appropriate design of the diffuser walls. The further wall of the diffuser is advantageously designed similar to the outer diffuser wall. Accordingly, the further wall advantageously has an angular cross-section at least at the outlet.

The sides of the further diffuser wall are advantageously continuously curved into each other.

The diffuser according to claim 10 is characterized in that the further diffuser wall at the inlet has a round, preferably circular outline, which merges continuously over the height of the further diffuser wall into the angular cross-section. Thus, even when using at least one other diffuser wall, the flow conditions are much better.

The diffuser according to the invention according to claim 1 1 is characterized in that the transitions between the sides of the further angular diffuser wall in the height direction have a twist or a twist.

In the diffuser of claim 12, optimal conditions arise. By choosing the angle between the two radials and the ratio between the diameter of the fan and the axial length of the diffuser, the flow conditions can be optimally adapted to the particular application. The relationship between this angle and the aspect ratio does not only apply to the diffuser outer wall but also to any other diffuser walls that may be provided. The value for all walls may be the same, but also different from wall to wall.

An advantageous embodiment results when the twist is in a range between about 50 ° and about 100 °

The diffuser according to claim 14 is characterized in that the ratio of inlet cross section to outlet cross section of the diffuser in a range <about 5, preferably between about 1, 2 and about 3, is located. By choosing the inlet and the outlet cross-section in relation to each other The efficiency of the diffuser can be perfectly adjusted to the application.

The diffuser according to claim 15 has the two walls whose outlet ends to increase the outflow of the diffuser are at different heights. By selecting the appropriate height of the walls, the size of the outflow surface can be adapted to the application.

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

The entrance ends of the walls may lie in a common plane.

However, it is also possible in another advantageous embodiment that the inlet ends of the walls lie in different planes, that is, have different distances from the inlet cross-section of the diffuser. Such a design of the diffuser leads to a particularly low-loss training.

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

In this case, the opening may be a gap extending over at least part of the circumference of the corresponding diffuser wall. But it is also possible to use as passages recesses, punched or transverse slots, these different configurations of the openings can also be used in combination with each other on the inner wall of the diffuser. If the diffuser has, in addition to the outer wall, more than one further wall, then these openings can be provided in at least one of these further walls, but also in two or more of the further walls. Also in the outer wall of the diffuser such openings may be provided.

The fan according to the invention according to claim 21 is characterized in that the transitions at the outlet end between the sides of the wall have a curvature which lies in a range of approximately <0.5 × D. In this way, the transitions at the outlet end can be designed so that optimal flow conditions arise.

The curvature is advantageously in a range of approximately <0.25 × D.

In an embodiment of the fan according to claim 23, 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.

In the fan according to claim 24, the ratio of the axial length of the diffuser to the diameter of the fan in a range of about <5, preferably between about 0.2 and about 2. Thus, the efficiency of the diffuser can be adjusted to the specified installation conditions. In the fan according to claim 25, the diffuser is configured so that the transitions between the sides of the diffuser wall in the height direction have a twist that follows the twist of the flow of air through the diffuser.

The fan according to claim 26 is characterized in that the diffuser has the further wall, which has the round, preferably circular cross-section at the inlet, which merges over the height of the further wall steadily into a polygonal cross-section.

The fan according to claim 27 has the diffuser, which is formed so that the transitions between the sides of the further wall in the height direction have a twist or a connection.

The fan according to claim 28 is characterized in that the diffuser has a wall which transitions over the height of the wall from a circular inlet cross-section into an angular outlet cross-section, the transitions between the sides of the wall in the height direction having a twist taking into account the angle between the two radials and the diameter of the fan and the axial length of the diffuser is configured.

In the fan according to claim 29, the diffuser is designed so that the ratio of inlet cross section to outlet cross section in a range <about 5, preferably between about 1, 2 and about 3, is located.

The fan according to claim 30 has the diffuser, whose at least two walls are formed so that their outlet end to increase the outflow surface is at different heights.

The device according to the invention according to claim 31 is designed such that the upper side of the housing side wall can be used optimally for the arrangement of the diffusers. At least two fans with diffusers are arranged on the upper side of the housing. These ventilators can be arranged with diffusers on each suitable side of the device housing.

Advantageously, the diffusers have a square outlet cross-section. The angular design makes it possible to place the plurality of diffusers with only a small distance next to each other, so that in devices in which only a limited amount of space is available and multiple diffusers are used, these can be arranged directly next to each other in one or more rows. If the outlet cross sections have a quadrangular outlet cross section, adjacent diffusers with their respective contour sides can be arranged adjacent to one another or with only the smallest distance next to and behind one another. As a result, the housing side is optimally used to delay the flow velocity.

The outline shape of the diffusers at the outlet end preferably depends on the outline shape of the housing side on which the diffusers are provided. As a result, the surface of the housing side can be optimally covered with corresponding diffusers, the housing side can be used optimally.

The subject of the application results not only from the subject matter of the individual claims, but also by all the information and features disclosed in the drawings and the description. They are, even if they are not the subject of the claims, claimed as essential to the invention, as far as they are new individually or in combination over the prior art.

Further features of the invention will become apparent from the other claims, the description and the drawings.

The invention is explained below with reference to some embodiments shown in the drawings. Show it 1 is a perspective view of a housing arranged outlet diffuser according to the invention of fan units,

2 shows a perspective and enlarged view of the outlet diffuser according to the invention,

3 is a rear view of the outlet diffuser according to FIG. 2, FIG.

4 shows a rear view of a further embodiment of an outlet diffuser according to the invention,

5 is a plan view of the outlet diffuser of FIG. 4,

6 shows the outlet diffuser according to FIG. 5 in a perspective view, FIG.

Fig. 7 is a rear view of an outlet diffuser with a twist in the

walls

Fig. 8, the rounding at the transitions between the sides of

Walls of the outlet diffuser and the area ratio between a quadrangular and a rounded at the ends square outlet cross-section,

Fig. 9

and

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

1 1 in a simplified representation of another embodiment of an outlet diffuser according to the invention,

12 shows a device with fans according to the prior art, 13 shows in axial section a further embodiment of an outlet diffuser according to the invention,

14 is an axial sectional view of another embodiment of an outlet diffuser according to the invention,

15 shows an axial section of a further embodiment of an outlet diffuser according to the invention,

16 is a perspective view of another embodiment

an outlet diffuser according to the invention.

Fig. 1 shows a schematic representation of a housing 1 of a device 2, which is a heat exchanger by way of example. The device 2 is a stand-alone device in the illustrated embodiment, but may also be a device mounted on a wall, a ceiling and the like. The device 2 has a plurality of fans 3, which are arranged by way of example in two rows with a small distance one behind the other. The fans 3 can be provided pressing or suction on the device or integrated into the device 2.

The fans 3 each have an outlet diffuser 4 (hereinafter referred to as a diffuser) by which leakage losses are minimized by converting the velocity of the exiting air into pressure.

The diffusers 4 are provided on the rectangular top 5 of the housing 1. To make optimum use of this rectangular top 5, the diffusers 4 have a quadrangular outline. This results in a particularly high increase in efficiency. The square shape leads to a large exit surface for the exiting air. Also occurs by no flow separation. The diffusers 4 are exemplarily arranged so that they touch each other with their adjacent edges, as shown particularly in Fig. 1.

Based on Fig. 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. At the outer edge 7 of the interface 6 includes a wall 8, which initially has a circular cross section and at a distance from the outer edge 7 continuously merges into a quadrangular outline. 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. But it is an embodiment possible in which the corners are really sharp at the outlet end of the diffuser.

Basically, the only wall 8 is sufficient for the diffuser 4 as a diffuser wall. In the embodiment of FIG. 2, two intermediate walls 9 and 10 are provided, which have over their height distance from each other, so that between the two partitions 9 and 10, a passage 11 is formed. Also between the intermediate wall 9 and the outer wall 8, there is a distance over the entire wall height, so that between the two walls 8 and 9, a further passage 12 is formed for the air. The passages 11, 12 have a quadrangular shape. The intermediate walls 9, 10 have the transition from a circular interface 13, 14 in the quadrangular shape as the jacket 8, wherein the quadrangular shape is to be understood in the same manner as in the wall 8. The interfaces 13, 14 have smaller diameter than that Interface 6, wherein the interface 14 of the inner intermediate wall 10 has smaller diameter than the interface 13 of the middle partition 9. The interface 14 advantageously has approximately the same diameter as the hub 21 (FIG. 9) of the impeller 20. The walls 8 to 10 are designed so that the outline of the walls towards their free end increases, preferably steadily increases. The walls 8 to 10 thus have the largest outline at the free end.

The course of the walls 8 to 10 may be formed so that they extend from the interface 6, 13, 14 at least approximately parallel to each other. Depending on the flow conditions, however, the walls 8 to 10 may also be designed such that they do not extend parallel to one another.

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

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

The partitions 9, 10 are fixedly connected to each other and with the outer wall 8 in a suitable manner, for example by cross struts, with which the walls are interconnected.

The four sides 34 to 37 (FIG. 7) of the walls 8 to 10 merge into one another continuously. The transition can, as shown by way of example in FIG. 4, take 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 course over the height of the wall 8 is indicated by the lines 15 in FIG. 4. The transition region 5, 16 extends almost over the entire height of the wall 8. The curvature is provided so that the transitions 15, 16 have a twist and the flow direction of the air behind the (not shown) impeller of the fan 3 follow. As is apparent from Fig. 7, the curvature is provided so that the transition regions 15, 16 form an angle along their length with a radial of the diffuser, which extends through the rounded corner 16 of the wall 8. Due to the course described occur only very small flow losses through the transitions 15, 16 at most. Due to the curvature, the transitions 15, 16 follow the swirl of the air flow within the diffuser 4. The Ü-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 provided with such transitions 17, 18, which are also curved according to the flow of air behind the impeller curved like a spiral and from the transition areas between the sides of the intermediate walls 9, 10 from close to the respective interface 13, 14 extend.

In the embodiment according to FIGS. 4 to 7, all the walls 8 to 10 are provided with the curved transitions. But it is also possible to provide these tortuous transitions only on one or only two of the walls 8 to 10 of the diffuser 4. Thus, in conjunction with the outline design of the walls 8 to 10, an optimal adaptation to the respective desired flow conditions can be achieved.

The approximately over the height of the walls 8 to 10 extending transitions 15, 16; 17, 18 may also extend, as seen in the axial direction of the diffuser 4, straight, again these transition areas include an angle with the radial of the diffuser.

In the described embodiments, the walls 8 to 10 have a square outline. But you can also have rectangular, hexagonal or, for example, 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 shape of the stream Outflow can thus be chosen so that the available housing side is optimally utilized.

The described twisting (twist) between the sides of the walls 8 to 10 is indeed an advantageous embodiment in the diffusers 4, but it is not absolutely necessary. In particular, in connection with the dimensions or dimensional ratios to be described, the diffusers 4 are characterized by no twisting (twist) at the transitions between the sides of the walls by excellent properties for use.

Fig. 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 wings 22 protrude at equal intervals. They are advantageous at the radially outer edge, each with a

Winglet 23 provided. The rear in the direction of rotation edge 24 of the wings 22 is profiled tooth-like.

The wings 22 of the impeller 20 may 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 dotted 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 integrally formed with each other, but may also be separate components that are firmly connected together in a suitable manner. The nozzle plate 32 advantageously has the same angular outline as the outlet end of the wall 8. As a result, the fans 3 can be 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 abut each other, as shown in Fig. 1. The diffuser 4 has the outer wall 8 and the intermediate walls 9, 10. In axial section, as is apparent from Fig. 9, the sides of the outer wall 8 are approximately concave. The sides of the intermediate wall 9 extend in an axial section approximately straight, while the sides of the intermediate wall 10 have an approximately convex course. Such a design of the walls 8 to 10 may be provided in all described embodiments.

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

The walls 8 to 10 of the diffuser 4 can be designed to dampen noise in the described embodiments, so that only a quiet operating noise arises in use of the fans. The walls 8 to 10 may also be designed to be adjustable in the described embodiments, so that they can be adapted in their outline shape at least over part of their height to the flow conditions and / or installation conditions. The walls 8 to 10 may be designed to be flexible over at least part of their height, for example, for adjustability.

FIG. 10 shows the possibility of axially fixing the diffuser 4 to the nozzle 19 of the fan 3. For this purpose, the interface 6 of the outer wall 8 may be provided with a radially outwardly extending annular flange 27 which is axially secured to a radially outwardly extending annular flange 28 at the free end of the nozzle 19. This axial attachment is also advantageous a screw connection, which makes it possible to remove the diffuser 4 from the nozzle 19 as needed. The diffuser 4 can be built relatively short due to the intermediate walls. The air conveyed by the impeller 20 passes between the walls 8 and 9 or 9 and 10. The flow cross-section of the passages 1 1 and 12 initially decreases in the flow direction until it has its smallest cross-section in the region 29 indicated by a dashed line. The air is accelerated within this range 29, which leads to a homogenization of the air flow. The air flow can then be delayed with lower losses, resulting in a high efficiency of the diffuser 4. From the region 29, the flow cross section of the passages 11, 12 increases in the direction of the outlet end, preferably continuously. The cross-sectional constriction 29 also prevents premature stalling (breakdown of the flow) in the passage 11 and 12.

Fig. 1 1 shows an exemplary and advantageous use of the diffuser 4. The inner partition wall 10 surrounds a terminal box 30 or a place for the electronics when the fan 3, an external rotor motor is used. In an internal rotor motor, the part 30 would be the motor of the fan. The air flow generated by the fan 3 flows through the passages 1 1, 12. The air flow flowing through the passage 11, the surface of the motor 30 is well cooled, whereby an effective cooling of the electronics or electrical components of the engine is achieved.

The outer wall 8 of the diffuser 4 is formed integrally with the nozzle 19 in the embodiment of FIG. 1 1. The exit region of the two passages 11, 12 is covered by a contact protection 31, which may be formed by a corresponding grid or by individual bars. The contact protection 31 has a large distance from the rotating impeller 20. The contact protection 31 can thereby be formed so that only small pressure losses occur when the air exits the diffuser 4 and only a small noise occurs. This effect can be achieved in particular by the contact protection 31 having a correspondingly large mesh size. The described contact protection 31 may be provided in all described and illustrated embodiments.

The diffuser 4 of the described embodiments can be used for evaporators, condenser, air cooler, recooler and the like. As described with reference to FIGS. 9 to 11, the diffuser 4 may be provided with a supporting function for receiving the fan motor 30.

The fans 3 may be axial or diagonal fans. The diffuser 4 may, if it does not have a swirl-having transition region 15, 16; 17, 18 in the walls 8 to 10, also be used for centrifugal fans.

The radius R at the exit end of the wall 8 (Figure 7) is advantageously in a range of <0.5 x D, where D is the diameter of the impeller 20 (Figure 9). In an advantageous embodiment, the radius R of the rounded corners of the wall 8 in a range <about 0.25 x D. This design is valid for both diffusers 4 with and without twisting (twist).

As is apparent from Fig. 8, the exit surface of the wall 8 is smaller due to the rounding of the corners than in a quadrangular outline at the exit end. The area deviation A / A _R of 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 appropriate choice of the radius R of the rounded corner can thus be provided an optimal outlet cross section of the wall 8 of the diffuser 4, so that the diffuser can be adapted to the given installation conditions. The ratio described can be applied in principle to the walls 9 and 10. The fillet does not have to be part of a circular arc (radius R), but can also have other shapes. The described area ratio applies to diffusers with and without distortion (twist). Also, the efficiency of the diffuser can be optimally adjusted by the ratio of length L to diameter D of the fan 3 to the predetermined installation conditions. This length-diameter ratio L / D is in a range of <5, preferably in a range of about 0.2 to about 2. This ratio applies to all described embodiments, especially for diffusers without twisting (twist).

Also can be taken by the choice of the inlet and outlet cross-section in relation to each other influence on the efficiency of the diffuser 4. In Fig. 9, the inlet cross-section with A _E and the outlet cross-section of the diffuser 4 is designated A _A. The ratio of exit surface to entry surface A _A / A _E 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, in particular for diffusers without distortion (twist).

The twist or twist 15, 16 described with reference to FIGS. 4 to 7; 17, 18 is defined by the relationship θ x, where the angle Θ between the two radials n and r _{2 is} measured. The Radial extends through the intersection region between the transition region 15 with the inner free edge 7 of the wall 8. The radial r ₂ runs in contrast to lying in the exit surface corner region of the wall 8 from which the transition region 15 extends. This twist or swirl θ x is in a range between 0 ° and 360 °, but advantageously in a range between about 50 ° and 100 °.

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

The following exemplary embodiments according to FIGS. 13 to 16 are designed so that the outlet speed can be further reduced by a larger outlet area of the diffusers, and thus the efficiency can be increased considerably. Fig. 13 shows a diffuser 4, which is similar to the embodiment of FIG. 10 axially fixed to the nozzle 19 of the fan. The diffuser 4 has except the outer wall 8, the intermediate walls 9, 10 and 38. They are each circumferentially formed and limit passages 1 1, 12, 39, 40, through which the air sucked by the fan flows. The walls 8 to 10, 38 are each formed curved over their height and arranged so that the flow cross-section of the passages 1 1, 12, 39, 40 increases in the flow direction. The inner intermediate wall 38 surrounds at a distance a central guide body 41, which continues the outer contour of the hub 21 of the impeller 20 of the fan 3 and continuously tapers from the hub 21 in the flow direction of the air until it runs out in a point. The guide body 41 is formed approximately conically with a curved cone sheath line.

Instead of the guide body, the diffuser 4 may also have a peripheral wall 41 according to the previous embodiments.

The walls 8 to 10, 38, 41 of the diffuser 4 are formed so that their outlet ends are at different heights. In the illustrated embodiment, the outlet ends of the walls, as viewed in axial section, lie on a circular arc 42. The center of the circular arc 42 is located on the axis 43 of the guide body 41 in the region between the hub 21 and the Leitkörperspitze. The Leitkörperspitze itself lies on the arc 42.

The inflow end 46 of the walls 8 to 10, 38, 41 is at the same level, while the outlet ends of the walls are arranged at different heights on the circular arc 42. The height of the walls increases from the wall 8 to the intermediate wall 38 and the jacket of the guide body 41. Due to the different height of the walls 8 to 10, 38, 41 results in a large diffuser exit surface A _A , which is characterized in axial section through the arc 42. The diffuser inlet surface A _E is substantially smaller than the diffuser exit surface A _A. The larger the ratio of diffuser outlet area A _A to diffuser inlet area A _E , the more dynamic Energy of the airflow at the diffuser inlet is converted to pressure energy.

The outline shapes of the diffuser walls 8 to 10, 38, 41 may be square or round. In an exemplary embodiment with only round cross-sections of the diffuser walls 8 to 10, 38, 41 results in a diffuser exit surface AA, which lies approximately on a Kalottenfläche, for example on a hemisphere surface. The calotte surface is considerably larger than diffuser walls whose outlet ends lie in a flat surface whose width corresponds to B _A. The inflow edges 46 of the walls 9, 10, 38, 41 are in this embodiment in a common radial plane of the diffuser 4, but can also be at different heights.

A particularly advantageous embodiment results when the diffuser walls 8 to 10, 38, 41 at the outlet end at the angle γ of about 90 ° to the associated tangent to the circular arc 42 and thus to the imaginary diffuser exit surface AA.

In principle, the end regions of the diffuser walls 8 to 10, 38, 41 can also lie at different angles γ to the circular arc 42.

The diffuser exit surface can also be designed so that it has the shape of a half ellipse in axial section. The length of a semi-axis, which extends transversely to the fan axis is limited by the available space. The length of the other semi-axis, which is parallel to the fan axis, can be made larger, whereby the diffuser exit surface A _A is increased accordingly.

Through the combination of diffuser walls with an angular and round outline, the size of the exit surface A _{A can be} maximized by means of different axial heights of the diffuser walls for a given installation space.

FIG. 14 shows, in an axial section, a further possibility of enlarging the diffuser exit surface A _A in comparison to the diffuser entry surface A _e . In the Difference to the previous embodiment, the exit surface A _A in axial section has a U-shape. If the diffuser walls are rectangular in outline, for example, then the exit surface A _{A is provided} at the outer sides of an imaginary cuboid 44 which are at right angles to one another. If, on the other hand, the diffuser walls have a round, for example circular, outline, the exit surface A _A lies approximately on the cylinder jacket of an imaginary cylinder 45.

In Fig. 14, the exit surface A _A in axial section through the dashed line. As a result, the air drawn in by the fan exits on different sides of the diffuser. The ratio between the diffuser exit surface A _A to the diffuser inlet surface A _E is very large, so that a lot of dynamic energy of the air flow is converted into pressure energy and the efficiency is significantly increased.

In the rectangular outline of the exit surface A _A shown in FIG. 14, viewed in axial section, the height H _{A of} the exit surface can be selected transversely to the fan axis, regardless of the installation space of the diffuser. Depending on the size of the height H _A , the exit area A _{A can} be increased more or less.

In the embodiment, the diffuser has a plurality of walls, each spaced from each other and form between them air passages.

The walls of the diffuser 4 are curved over their height. The walls are designed so that widens the flow cross-section of the passages between the walls in the flow direction. The walls may have round and / or angular outline. A part of the walls of the diffuser 4 opens into the side surfaces and a part in the end face of the diffuser. The walls of the diffuser 4 are each formed so that the outlet ends in the amount of the front side or the side surface (s) of the imaginary cuboid 44 and the imaginary cylinder 45 are. As is further apparent from Fig. 14, the entrance ends 46 are at different axial heights. Accordingly, the entrance ends 46 of the diffuser walls are at different distances from the diffuser inlet.

Such a design of the diffuser leads to a particularly low-loss design.

The guide body 41 is in turn centrally located and extends from the hub 21 upwards. The guide body 41 is conical in shape, with the apex of the cone lying in the end face of the imaginary cuboid 44 or of the imaginary cylinder 45. Instead of the guide body of the diffuser 4 may have a circumferential wall 41 according to the embodiments of FIGS. 1 to 1 1.

The various walls of the diffuser 4, as has been described with reference to the previous embodiments, interconnected by (not shown) narrow webs together. By varying the height H _A , the exit surface H _{A of} the diffuser can be easily varied and adapted to the application.

The cuboid or cylindrical configuration of the outline of the diffuser 4 in the embodiment according to FIG. 14 is only to be understood as an example. The diffuser can also have the shape of an isosceles triangle in axial section, for example, whose axis of symmetry is the fan axis 43. The walls of the diffuser are then also of different heights and arranged so that the exit ends of these walls lie in the sides of the triangle. If the diffuser walls have a round outline, an equilateral triangle results in an axial outline of the conical shape of the diffuser. If the walls are square, roughly quadrangular in outline, the result for the diffuser is a square or four-sided pyramid. The exit area A _A in such embodiments, as in the embodiment according to FIGS. 13 and 14, is substantially larger than the diffuser entry area A _E. The exit ends of the walls can be like lie in the previous embodiment at about 90 ° to the side surfaces and also to the end face of the diffuser 4.

In the embodiments according to FIGS. 13 and 14, the diffusers in combination may have walls with a round and angular outline.

A particularly advantageous embodiment of a diffuser is shown in FIG. 15. The diffuser 4 has a similar design to the embodiment according to FIG. 10. The diffuser is connected to the 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 wings 22 protrude at equal intervals. They are advantageously provided on the radially outer edge, each with a winglet 23. The rear in the direction of rotation edge 24 of the wings 22 is advantageously profiled, in particular profiled tooth-like. The wings 22 are advantageously formed wound.

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

The diffuser 4 may be connected to the nozzle 19 radially or axially, as has been described with reference to FIGS. 9 and 10.

The nozzle 19 is provided on the 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 integrally formed with each other, but may also be separate components, which are firmly connected together in a suitable manner. The nozzle plate 32 advantageously has the same angular outline as the outlet end of the wall 8. As a result, the fans with the diffusers 4 can be arranged closely behind and / or next to one another. The nozzle plates 32 and the walls 8 of the diffusers 4 of adjacent fans 3 can abut each other here, as shown by way of example in FIG. The outer wall 8 is approximately concave in axial section. The sides of the intermediate wall 9 are approximately straight in axial section, while the sides of the intermediate wall 10 have an approximately convex course in axial section.

In the flow direction behind the impeller 20, the guide vanes 26 may be provided in the diffuser 4, which extend between the walls 8 to 10 and are arranged rigidly. The guide vanes 26 are located on the side facing away from the wings 22 side of the attachment 25, via which the diffuser 8 is connected to the nozzle 19. The diffuser 4 is pushed with its interface on or in the nozzle 19.

The walls 8 to 10 can be designed to dampen noise, so that the use of the fans produces only a quiet operating noise. The walls 8 to 10 can be designed to be adjustable, so that they can be adapted in their outline shape at least over part of their height to the flow conditions and / or installation conditions.

The intermediate wall 9 consists of two slightly overlapping wall sections 9a and 9b. The overlap area is designed so that a gap 47 results, which leads to a positive fluidic effect. Part of the air flowing through the passage 1 1 passes through the air gap 47 and thereby passes into the passage 12. Through this gap 47, which extends advantageously over the circumference of the intermediate wall 9, the boundary layer flow in the axially outer passage 12 by means of accelerated by high-energy flow of the inner passage 1 1. As a result, a flow separation in the further outward passage 12 is prevented or at least delayed. In this way, the energy efficiency of the diffuser 4 is increased.

The overlap of the two wall sections 9a, 9b may be designed such that part of the air flows from the inner into the outer passage or from the outer into the inner passage.

The annular gap 47 may be interrupted by webs or the like, through which the two wall sections 9a, 9b in the overlapping region be connected to each other. The diffuser may also be provided at other locations with corresponding columns 47.

Fig. 16 shows a diffuser 4, in which the intermediate wall 9 is provided with recesses 48 or slots 49, through which a similar action is achieved as through the gap 47 of the diffuser of FIG. 15. Through these recesses or slots is high-energy fluid from a passage in the boundary layer of the adjacent passage to avoid Grenzschichtablösungen or at least reduce.

The recesses 48 are advantageously distributed over the circumference of the intermediate wall 9.

The recesses 48 and the slots 49 may also be provided in combination on the intermediate wall 9. These recesses and slots may be provided on each of the walls of the diffuser 4 at any location and in any suitable distribution. This also applies to the gap 47 of the diffuser 4 according to FIG. 15.

Incidentally, the diffuser 4 is the same design as the embodiment according to FIG. 2, so that reference is made to the description of the diffuser there.

Claims

claims

1 . Diffuser having at least one wall (8) enclosing an inlet of circular cross-section, which merges over the height of the wall (8) of the diffuser (4) into an angular cross-section at the outlet of the diffuser (4), characterized in that the transitions (15) between the sides (34 to 37) of the wall (8) in the height direction have a twist that follows the swirl of the flow of air through the diffuser.

2. Diffuser according to claim 1,

characterized in that the wall (8) has an angular outline.

3. Diffuser according to claim 1 or 2,

characterized in that the sides (34 to 37) of the wall (8) continuously curved into each other.

4. Diffuser according to one of claims 1 to 3,

characterized in that the cross section of the diffuser (4) increases in the flow direction.

5. Diffuser according to one of claims 1 to 4,

characterized in that the cross section of the diffuser (4) from the inlet end (6) initially decreases and then increases.

6. Diffuser according to one of claims 1 to 5,

characterized in that the angular cross-section over more than a quarter of the height of the wall (8) is provided.

7. Diffuser according to one of claims 1 to 6,

characterized in that the diffuser (4) has at least one further wall (9, 10) which is surrounded by the wall (8) at a distance.

8. Diffuser according to claim 7,

characterized in that the further wall (9, 10) has at least at the outlet angular cross-section.

9. Diffuser according to claim 8,

characterized in that the sides of the further wall (9, 10) continuously curved into each other.

10. Diffuser, in particular according to claim 8 or 9,

characterized in that the further wall (9, 10) at the inlet has a round, preferably circular cross section, which merges over the height of the further wall (9, 10) steadily into a polygonal cross section.

1 1. Diffuser, in particular according to one of claims 8 to 10,

characterized in that the transitions (17, 18) between the sides of the further wall (9, 10) in the height direction have a twist (twisting).

12. A diffuser having at least one wall (8) enclosing an inlet of round cross section, which merges over the height of the wall (8) of the diffuser (4) into an angular cross section at the outlet of the diffuser (4), characterized in that the transitions (15) between the sides (34 to 37) of the wall (8) in the height direction have a twisting (15 to 18) satisfying the relationship θ x -, wherein the angle (Θ) between two radials (r1 and r2 of which one radial (r1) passes through the intersection between the transition (15) and the free edge (7) at the inlet of the wall (8) while the other radial (r2) is from the axis of the inlet extends to the outlet corner area of the wall (8) from which extends the transition (15) extends, each viewed in the axial direction of the diffuser (4). 3. Diffuser according to claim 12,

characterized in that the twist is in a range between about 50 ° and about 100 °.

14. Diffuser, in particular according to one of claims 1 to 13,

characterized in that the ratio of inlet cross section (AE) to outlet cross section (AA) in a range less than about 5, preferably between about 1, 2 and about 3, is located.

15. Diffuser, in particular according to one of claims 1 to 14, having at least one wall (8) having an inlet and an outlet, characterized in that the wall (8) to form a passage (1 1, 12, 39, 40) at least one further wall (9, 10, 38, 41) surrounds, and that the outlet ends of the walls (8 to 10, 38, 41) to increase the outflow surface (A _A ) of the diffuser (4) are at different heights.

16. Diffuser according to claim 15,

characterized in that the outlet ends of the walls (8-10, 38, 41) lie in a curved surface, such as a spherical or cylindrical surface (45).

17. Diffuser according to claim 15,

characterized in that the outlet ends of the walls (8 to 10, 38, 41) lie in flat surfaces which are, for example, side surfaces of an imaginary cuboid (44) or a pyramid.

18. Diffuser according to one of claims 15 to 17,

characterized in that the outlet ends of the walls (8-10, 38, 41) lie in a common plane.

19. Diffuser according to one of claims 15 to 17,

characterized in that the outlet ends of the walls (8-10, 38, 41) lie in different planes.

20. Diffuser according to one of claims 15 to 19,

characterized in that in at least one wall (8 to 10, 38, 41) at least one opening (47, 48, 49) is provided, through which adjacent passages (1 1, 12, 39, 40) are flow-connected with each other.

Fan with an impeller (20) and a diffuser (4), in particular according to one of claims 1 to 20, having at least one wall (8) enclosing an inlet of round cross-section, which is above the height of the wall (8) merges into an angular cross-section at the outlet of the diffuser (4),

characterized in that the transitions (15) at the exit end between the sides (34 to 37) of the wall (8) have a curvature (R) which is in a range of approximately <0.5 x D, where (D) the Diameter of the impeller (20) is.

22. Fan according to claim 21,

characterized in that the curvature (R) is in a range of about <0.25 × D.

23. A fan, in particular according to claim 21 or 22, with an impeller (20) and a diffuser (4), in particular according to one of claims 1 to 20 is formed and at least one wall (8) having an inlet and an outlet limited,

characterized in that the exit area (A _R ) of the wall (8) with the rounded transition (15) is smaller than the exit area (A) of the wall (8) without a rounded transition (15) at the exit end between the sides (34 to 37 ) of the wall (8), wherein the surface area (A / AR) ranges between about 1 and about 1.27, preferably between about 1 and about 1.05.

Fan with an impeller (20) and a diffuser (4), which is designed in particular according to one of claims 1 to 20 and has at least one wall (8) which has an inlet and an outlet,

characterized in that the ratio of the axial length (L) of the diffuser (4) to the diameter (D) of the fan (3) is in a range of about <5, preferably between about 0.2 and about 2.

25. Fan with a diffuser according to one of claims 1 to 9.

26. Fan with a diffuser according to claim 10.

27. Fan with a diffuser according to claim 1 1.

28. Fan with a diffuser according to claim 12 or 13.

29. Fan with a diffuser according to claim 14.

30. Fan with a diffuser according to one of claims 15 to 20.

31. Device with at least one fan according to one of claims 21 to 30.

32. Device having a housing (1) which has at least one side wall with an upper side (5) on which a fan (3) with a diffuser (4) is arranged, in particular according to one of claims 1 to 20,

characterized in that on the upper side (5) of the housing side wall at least one further fan (3) with a diffuser (4) is arranged.

33. Apparatus according to claim 32,

characterized in that the diffusers (4) have square outlet cross section.

34. Apparatus according to claim 32 or 33,

characterized in that adjacent diffusers (4) lie with their contour sides together.