EP1961968A1 - Radial fan wheel and radial fan incorporating the same with locking protection - Google Patents

Abstract

The radial-impeller has an actuated support part (18). The support part is carried radially within the impeller blades (20) additionally from the support part to auxiliary blades (44) protruding axially. The auxiliary blades are engaged at normal level of the axis of the rotation (12), in which conveyance fluid contains particles that are impinged with a force component aligned away from the support part. An independent claim is also included for a radial blow fan with an exhaust wheel.

Description

The invention relates to an axial impinged radial impeller according to the preamble of patent claim 1.

Such fan wheels are for example from the documents EP 0615069 A1 . EP 1530682 B1 or DE 10315341 B4 known.

Such a known fan wheel is used primarily where it comes to pumping fluid from an environment that is loaded with considerable amounts of particles in solid and / or liquid form. The radial fan equipped with the fan has on the side facing away from the carrier part an inlet for the fluid and the fan carries a blade assembly in the form of a blade ring, between the individual blades radial channels are defined by the radially outwardly deflected from the axial direction fluid to the outside flow and can escape there from the impeller. In correspondingly equipped radial fans, the impeller is usually installed in a blower housing with such a fit that it is surrounded by an annular channel with an outlet.

Frequently, the fluids or fluids to be delivered by such radial fans are loaded with abrasive substances, such as solid or suspended water or fat droplets or dust particles. In order to separate these particles from the fluid flow, filters can always be upstream or downstream. But these filters have the disadvantage that they must be maintained consuming to keep the pressure drop in the flow within tolerable limits. So that the expense of depositing the particles can be kept small and yet the separation and delivery efficiency at a high level, the fan wheels are given the task to effectively deposit these particles - at least in part - as it flows through the fan before exiting the fan.

For this purpose are according to EP 0615069 A1 between the Lüfterradschaufeln and usually close to the support member of the fan guide plates provided with which a radially outward gas flow is to be generated near the support member. Radially outside of the support member and adjacent to the annular channel in which the cleaned fluid flows, a radially open annular gap is formed with a small axial width through which as many particles can be discharged into a further annular chamber.

According to EP 1530682 B1 respectively. DE 10315341 B4 In order to achieve an improved separation effect on the working side or pressure side of the fan blades, elevations or projections are arranged which extend substantially diagonally from the inflow edge of the blades towards the outlet edge.

However, these known fan wheels often have only insufficient service life, since the particles contained in the fluid lead to punctual high wear, which leads to an early replacement of the fan wheels. This wear is common at the blade root, i. particularly large at the blade edge in the transition to the carrier part.

The invention is therefore the object of developing a radial impeller of the type described above in such a way that the service life can be significantly increased, especially if the fluid to be pumped are loaded with abrasive particles.

This object is solved by the features of claim 1.

According to the invention, the support member is fitted radially within the fan blades with additional, axially projecting from the support member auxiliary blades, which are employed to the normal plane of the rotation axis such that in the fluid to be conveyed particles are acted upon by a directed away from the support member force component. It could be shown in tests that the service life of the fan wheel can be increased by 2 to 5 times with this measure.

Advantageous developments are the subject of the dependent claims.

If the fan blades and / or the additional blades in the direction of rotation of the fan are curved convex, concave or S-shaped, the flow characteristics of the fan can be improved.

If the auxiliary blades are circumferentially offset to the fan blades or even overlap with the fan blades in the radial direction, further improved protection of the fan blades from wear occurs.

The additional blades may have a height that varies in the radial direction. In this way, the fluidic losses are minimized.

If the additional blades are made of a wear-resistant material, the service life of the fan wheel can be further increased. Preferably, the additional blades are interchangeable, so that the life of the fan is further improved.

Preferably, the auxiliary blades have a maximum axial extent which is less than that of the fan blades, whereby the flow losses can be further reduced.

A radial fan according to the invention, which is equipped with a fan according to the invention is the subject of claims 14 to 17. This radial fan can simultaneously deposit a variable percentage of solid or liquid particles contained in the fluid through the annular channel with the outlet.

If the gap dimension MS of the radial channel is adjustable, the radial fan can be optimally adapted to the quality of the fluid to be delivered.

The invention can be combined with various designs of the fan wheel, including those in which the fan wheels an improved separation efficiency is transmitted.

In order to achieve a certain, improved degree of separation of particles with the greatest possible wear protection when the fluid to be pumped and at the same time is loaded with large amounts of particles, the fan blades can be adjusted to the normal plane of the rotation axis at such an angle or obliquely that in the Particles to be delivered fluid can be acted upon under the influence of centrifugal and Coriolis force with a force component directed towards the carrier part. Thus, the particles contained in the fluid during flow through the fan or the trained between the Lüferradschaufeln flow channels are urged directly into the area near the support member, so that they at the radially outer end of the support member, ie when leaving the fan, on the separation annular gap can be separated from the fluid flow. When the angle of attack of the fan blades with respect the normal plane to the axis of rotation varies in the radial direction, the deposition effect can be further optimized.

It has been shown in experiments that with extremely highly particle-loaded fluids separation efficiencies can be achieved, which are far above those which could be realized with conventional constructions.

This results in the additional advantage that the impeller according to the invention operates quieter and with a higher fluidic efficiency, as equipped with additional fins fan wheels, and yet not prone to local particle accumulation, which can be hearbsetzen the maintenance. In this way, the fan according to the invention is also suitable for the coarse cleaning of fluids that are loaded with a mix of liquid and solid particles.

If the blades of the blade assembly form a blade ring with radially inward flow inlet edges and radially outer flow outlet edges, wherein the flow inlet edges and flow outlet edges each having a pitch circle associated, there is a rotationally symmetrical structure of the fan, whereby the manufacturing cost can be reduced ,

If the flow inlet edges extend from a hub portion of the carrier part axially away from the latter to a blade edge extending essentially parallel to the carrier part, a flow channel which is favorable for the fluid flow and has a substantially constant height in the radial direction results, a particularly compact form of the fan, which can be installed with little effort in a fan housing.

Straight or non-curved fan blades, with certain particle sizes and / or distributions, have advantages in terms of ease of maintenance, as they counteract the tendency for particle deposits. However, a particularly high degree of fluid-mechanical efficiency of the fan wheel arises when the fan wheel blades are curved in a convex manner in the direction of rotation of the fan wheel.

The fan may additionally be modified so that each fan blade on its working or pressure side receives at least one strip-like projection, which is employed to the flow direction in the flow channel between the blades such that the flow axially at least in printing side proximity on the support member is deflected, the strip-like projection terminates in a predetermined and small axial distance to the support member. With these projections, small liquid particles can be deposited effectively. Due to the additional blades according to the invention, it is possible to effectively control the wear on such projections, even if the height of the projections should be considerable. However, if the height H is in the mm range, the noise can be limited and at the same time a better efficiency can be achieved.

If the carrier part is formed by a plate, the construction of the fan wheel and thus of the radial fan is further simplified, with the particular advantage that the carrier part in operation does not tend to particle accumulations on its top.

If the fan blades on the side facing away from the support member wearing a ring and fixedly connected to this, for example, welded, the stability of the fan can be raised, with the result that the support member and / or the hub are made easier and a compound of the fan blades can be omitted with the hub.

An inventive radial fan, which is equipped with a fan according to the invention is the subject of claims 14 to 17.

Further advantageous embodiments are the subject of the remaining dependent claims.

• Figur 1 eine schematische Draufsicht eines Lüfterrads;
• Figur 2 den schematischen Schnitt gemäß II-II in Figur 1;
• Figur 3 die schematische Schnittansicht gemäß III-III in Figur 1;
• Figur 4 eine Draufsicht auf ein modifiziertes Lüfterrad gemäß der Erfindung; und
• Figur 5 eine schematische Schnittansicht des Radialgebläses mit einem Lüfterrad ähnlich demjenigen der Figuren 1 bis 4.

Embodiments of the invention will be explained in more detail with reference to schematic drawings. Show it:

• FIG. 1 a schematic plan view of a fan wheel;
• FIG. 2 the schematic section according to II-II in FIG. 1 ;
• FIG. 3 the schematic sectional view according to III-III in FIG. 1 ;
• FIG. 4 a plan view of a modified fan according to the invention; and
• FIG. 5 a schematic sectional view of the radial fan with a fan similar to that of FIGS. 1 to 4 ,

In the FIGS. 1 to 3 The reference numeral 10 generally designates an axially impinged radial impeller which serves to convey a fluid or fluid, in particular a fluid laden with solid or liquid particles. Such a fan can be used for example in a radial fan, which in FIG. 5 is shown schematically.

The impeller 10 is intended to be capable of handling fluids, in particular gaseous fluids, which may interfere with abrasive particles, e.g. Dust particles, water particles, snowflakes, fat particles and the like. Are loaded to pump effectively or pump out of an environment. Such fan wheels can also fulfill the task of largely separating these particles during the flow of the fan impeller. A specific field of application of the fan wheel is in the conveying / filtering function of fluids which have an extremely high proportion of entrained particles, wherein the wear on the fan wheel should be as low as possible.

The fan 10 has a rotation axis 12, which - as can be seen from the FIG. 5 detects, to which reference should already be made here - when mounted in a fan 14, for example, vertically aligned. However, the orientation of the axis 12 is arbitrary.

A designated 16 hub rotatably seated on a drive shaft, not shown, with the axis 12 and it carries a blade support member 18, which extends substantially perpendicular to the axis of rotation 12. The carrier part 18, in turn, carries a blade arrangement with a large number of fan wheel blades 20 arranged in the manner of a wreath at a circumferential distance from each other and, as a rule, identically designed.

The fan blades 20 are - as is apparent from the illustrations of FIGS. 1 and 4 yields - to an axis of rotation 12 containing axial plane 22, such as the plane of the FIG. 3 at a certain angle DELTA, so that they produce a radially outward flow when turning the fan 10 with the direction of rotation V. However, the angle DELTA can also be NULL.

The fan blades are aligned parallel to the axis of rotation 12, but they can also be employed to the normal plane 15, which coincides in the embodiment shown with the plane of the support member 18, at an angle <90 °, ie such that contained in the fluid to be conveyed particles under the influence of the dynamic forces, including the centrifugal and the Coriolis forces, are acted upon with a force component directed towards the support member.

In the embodiment shown the FIGS. 1 to 3 the fan blades 20 are straight. However, it should already be emphasized at this point that the blade shape can be modified as desired in order to improve the flow-mechanical efficiency of the fan and / or the particle separation to be described later.

The fan blades 20 each have a radially inner leading edge 24 and a radially outer trailing edge 26. Between the fan blades 20 substantially radially outwardly directed flow channels 28 are defined, so that therefore an axial inlet flow - in FIG. 5 denoted by the arrow SE - is at radially rotating fan 10 radially outward in an outlet flow SA with radial and directed in the circumferential direction speed component is deflected.

As the figures show, the leading edges 24 and flow outlet edges 26 each have a pitch circle 24a or 26a associated therewith. The flow entry edges 24 extend from a portion of the support member 18 proximate to the hub 16 and extend axially therefrom to a blade edge 29 substantially parallel to the support member 18 (see FIGS FIG. 3 ) or 229 (see FIG. 5 ).

In the embodiment according to the figures, the blades carry on the side facing away from the support member 18, an annular disc 21 and they are firmly connected to this, for example, welded. However, they can also end just below a top wall of the housing.

The shape of the Lüfterradschaufeln 20 can - depending on the fan design - vary within wide limits. When the fan blades 20 carry a dimensionally stable washer 21, as shown in the figures, the construction of the fan wheel becomes stiffer, so that it is sufficient to attach the fan blades to the support member 18, e.g. to weld. The leading edge 24 of the fan blades can then be arranged substantially parallel to the axis of rotation. On the other hand, a freely cantilevered shape of the blades has the advantage that no particle accumulations are formed in the fan.

In general, therefore, the flow inlet edges 24 of the fan blades 20 in the various sectional views perpendicular to the axis of rotation 12 on pitch circles 24a, which are part of a part of a circle, which a cylinder or truncated cone shell with a small cone angle WK (see FIG. 3 and 5 ) Are defined.

As is clear from the Figures 5 results, the fan 10 is installed in the housing 14 of the Radialgebläseso that it comes to rest below an axial inlet funnel or inlet nozzle 30 which is aligned with the axis of rotation 12 of the fan 10. Radially from the outside, the fan 10 is enclosed by an annular channel 32 having an outlet 34 for the fluid.

The annular channel 32 has a bottom surface 36 which closely conforms to the radially outer blade edges 26 while maintaining a small gap 37. For this purpose, the fan wheel 10 may also be provided with a bottom-side recess (not shown) into which the bottom surface 36 of the annular channel 32 engages with a fit. As is further from the FIG. 5 shows, the bottom surface 36 of the annular channel 32 to a support member 18 nearest edge 38 of the fan blades 20 axially spaced by a predetermined gap MS. In this way, the bottom surface 36 of the annular channel 32 defines a radial or annular gap 40 for discharging particles deposited from the fluid, such as dust, water, oil or grease particles.

The annular gap 40 is surrounded by a further annular chamber 42 for collecting and discharging the particles separated from the fluid.

On the support member 18 and on the hub 16 are radially 20 radially mounted within the Lüfterradschaufeln additional, axially projecting from the support member 18 additional blades 44, wherein the axial extent of the additional blades is less than that of the fan blades 20. The additional blades 144 are employed against the direction of rotation V, ie they close with the normal plane 15 to the axis of rotation 12 and with the plane of the support member 18 at an angle WA> 90 °, which manages the wear of the fan blades 20 and possibly attached thereto strip-like projections in FIG. 1 indicated only by dashed lines and designated by 48, to even.

To keep the effect of the additional blades 44 as large as possible, they are offset to the fan blades 20 in the circumferential direction, in such a way that the deflected by the additional blades 44 particles under the influence of fluid mechanical and other dynamic forces do not hit the leading edges 24 of the fan blades 20 , The additional blades 44 may also overlap in the radial direction with the Lüfterradschaufeln 20.

As in FIG. 1 indicated by dashed lines, each fan blade 20 can carry on its working or pressure side 46 at least one strip-like projection 48, which is employed to the flow direction in the flow channel 28 between the blades 20 such that the flow axially at least in Druckseitennähe to the support member 18 is deflectable and at a predetermined axial distance, preferably not greater than the dimension MS - see FIG. 5 - is, to the support member 18 ends.

The strip-like projections 48 preferably have a low height, which may be in the millimeter range, so that the flow losses do not increase. But it can also be up to 50% of the axial extent H of the fan blades 20.

With this design of the fan, the following operation of the radial fan results:

The highly particulate laden fluid, preferably gaseous fluid, such as air, enters the radial fan at 30. By the action of the fan blades 20 of the rotating at a predetermined speed fan wheel 10, the flow is deflected into the channels 28 and conveyed radially outward. Due to the additional blades 44 according to the invention and their employment according to the invention at an angle WA> 90 °, the wear caused by the particles on the fan wheel 10 can be evened out. In particular, the highly stressed blade roots 50 of the fan blades 20, but also the blade roots 52 of the additional blades 44 can be effectively protected against excessive and rapid wear.

The flow losses in the fan 10 due to the smooth design of the flow paths, very low, which also applies to the noise. Further, the fan 10 is not prone to particulate deposits, so that over a long period of operation, a maintenance-free operation results even if the particles are very abrasive and / or tend to stick together.

In the foregoing, an embodiment having straight fan blades 20 and auxiliary blades 44 has been described. With reference to the FIGS. 4 and 5 Variants are described with other designs of the blades. In this case, those parts of the fan, which correspond to the components of the arrangement described above, provided with the same reference numerals, but dennen a "1" or "2" is preceded.

At the in FIG. 4 shown variant, the fan blades 120 are convex in the direction V. The Lüfterradschaufeln 120 are smooth, so that there is a good efficiency and low noise.

At the in FIG. 5 indicated variant are on each Lüfterradschaufel 220, namely on the respective working or printing side 246 two substantially mutually parallel strip-like projections 248a, 248b provided that terminate at a substantially same axial distance MS to the support member 218.

An unillustrated angle of inclination, under which the projections 248a, 248b are made to the blade surface 246, can be set to a certain value, which is the composition of the fluid best in terms of wear minimization and / or Abscheidewirkungsgrad. The angle of attack or the surface design (also an arch shape is possible) of the protrusions 248 is preferably determined empirically depending on the type and consistency of the particles to be filtered out of the fluid.

The projections 248 are in the embodiment shown to the flow-leading edge 224 of the Lüfterradschaufeln 220 out, but they can also end in front of the edge 224.

As further from the FIG. 5 results, have the additional blades 244 an axial extent EA, which varies in the radial direction or becomes larger with increasing distance from the axis 12.

Of course, further modifications of the fan and the radial fan are possible without departing from the spirit of the invention.

The fan blades 20 may be turned to the circumferential velocity vector at an angle WS less than 90 °, whereby the particles contained in the fluid, which may be in solid or liquid form, are under the influence of fluidic forces, mass forces and other dynamic forces , as the centrifugal and the Coriolis forces, are urged towards the support member 18, so that in the area radially inside the annular gap 40 is a significantly larger particle concentration than in the rest of the flow. The particles contained in this ströungsschicht reach via the annular gap 40 in the annular chamber 42, which is preferably designed so that no excessive back pressure is built up therein. The main flow, the fan 10 above the annular gap 40th leaves is cleaned to a correspondingly high percentage. The adjustability of the measure MS can be influenced by the degree of separation efficiency as a function of the composition of the fluid to be cleaned.

Ach the angle of attack WS of the fan blades 20, 120, 220 can be varied with respect to the normal plane 15 to the axis of rotation 12 in the radial direction, so that there is a kind of propeller shape for the blades.

In the embodiment of the FIG. 4 the additional blades 144 as well as the fan blades 120 are convex. But they can also be straight or concave or S-shaped.

The strip-like projections 248a, 248b may also or be given a different shape, for example, be guided arcuately.

As material for the components of the fan, all common materials, such. metallic materials and plastics are used. Joining techniques, e.g. Welding or gluing techniques, but also found casting designs application.

The invention thus provides an axial impinged radial impeller for conveying a particle-laden fluid, with a driven support member which extends substantially perpendicular to a rotation axis and carries a blade assembly with a plurality of annularly spaced circumferentially spaced impeller blades, each having a have radially inward leading edge and a radially outer outlet edge and between which radially outwardly directed flow channels are fixed, whereby an axial inlet flow can be deflected radially outward. In order to effectively protect the components of the fan from wear and to increase the life of the fan, the support carries radially within the fan blades additional axially projecting from the support member supporting blades, which are employed to the normal plane of the rotation axis such that in the fluid to be conveyed particles with a force component directed away from the carrier part can be acted upon.

Claims (17)

An axial impinged radial impeller (10; 110; 210) for conveying a particulate laden fluid, comprising a powered support member (18; 118; 218) extending substantially perpendicular to an axis of rotation (12) and a plurality of vane assemblies each having a radially inner leading edge (24) and a radially outer outlet edge (26) and between which radially outwardly directed flow channels (28) are fixed, whereby a axial inlet flow (SE) can be deflected radially outward, characterized in that the support member (18; 118; 218) radially within the Lüfterradschaufeln (20; 120; 220) additional from the support member (18; 118; 218) axially projecting auxiliary blades (44 144; 244) which are set to the normal plane (15) of the rotation axis (12) such that particles contained in the fluid to be delivered with one of the support member (18; 118; 218) directed away force component can be acted upon. Fan wheel according to claim 1, characterized in that the fan blades (120) and / or the additional blades (144) in the direction of rotation of the fan are convex, concave or S-shaped curved. Fan wheel according to claim 1 or 2, characterized in that the additional blades (44; 144; 244) are offset in the circumferential direction to the fan blades (20; 120; 220). Fan wheel according to claim 3, characterized in that overlap the additional blades and the Lüfterradschaufeln in the radial direction. Fan wheel according to one of claims 1 to 4, characterized in that the additional blades (244) have a height EA, which changes in the radial direction. Fan wheel according to one of claims 1 to 5, characterized in that the additional blades (44; 144; 244) consist of a wear-resistant material. Fan according to one of claims 1 to 6, characterized in that the additional blades (44; 144; 244) have a maximum axial extent (EA) which is less than that of the fan blades (20; 120; 220). Fan impeller according to one of claims 1 to 7, characterized in that the fan blades (20) of the blade assembly form a blade ring with radially inner flow inlet edges (24) and radially outer flow outlet edges (26), wherein the flow inlet edges (24). and flow outlet edges (26) each have a pitch circle (24a, 26a) is associated. Fan impeller according to claim 8, characterized in that the flow inlet edges (24) from a hub portion (16) of the support member (18) axially away from this to a support member (18) substantially parallel blade edge (29; 229 ). Fan wheel according to one of claims 1 to 9, characterized in that the carrier part (18) is formed by a plate. Fan wheel according to one of claims 1 to 10, characterized in that the fan blades (20; 220) on the side facing away from the carrier part (18; 218) carry an annular disc (21; 221). Fan wheel according to claim 11, characterized in that the Teilkreisschar the flow-entry edges (24) defines a cylinder or truncated cone shell with a small cone angle (WK). Fan wheel according to one of claims 1 to 12, characterized in that the additional blades (44) have a height EA, which is up to 50% of the axial extent (H) of the fan blades (20). A radial fan with a fan wheel according to any one of claims 1 to 13, having an axial inlet (30) aligned with the axis of rotation of the fan wheel (10) and a housing (14) in which the fan wheel (10) is fitted such that it is surrounded by an annular channel (32) with the outlet (34), wherein the annular channel (32) has a bottom surface (34) extending snugly conforms to the radially outer blade edges (26) and is axially spaced from the edge (38) of the fan blades (20) closest to the support member (18) by a predetermined gap MS. Radial fan according to claim 14, characterized in that the bottom surface (36) of the annular channel (32) defines an annular gap (37) for the removal of separated particles, such as dust, water, oil or fat particles in the fluid to be delivered. Radial fan according to claim 15, characterized in that the width of the annular gap (37) is adjustable. Radial fan according to claim 16 or 17, characterized in that the annular gap (37) is surrounded by a further annular chamber (42) for collecting and discharging the particles separated from the fluid.

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