EP1589229B1 - Ventilator - Google Patents

Description

The present invention relates to a blower, in particular a combustion air blower for a heater, comprising a blower housing, a conveying channel formed in the blower housing and extending around an axis of rotation and open on one axial side, a conveying wheel which on the blower housing the conveying channel at its overlapping axially open side and rotatably supported about the rotation axis and having a plurality of circumferentially successive conveyor blades which move in a rotational direction over the conveyor channel upon rotation of the conveyor wheel, and an entrance area for entry of air to be conveyed into the conveyor channel such as it is defined in the preamble of claim 1.

Such generally also called side channel blower fan are preferably used to in vehicle heaters, such as. As auxiliary heater or heater, to initiate the combustion air required for combustion in a combustion chamber. With the rotation of the feed wheel, the air to be conveyed in the conveyor channel is set in a helical flow, whereby a gradual increase in pressure occurs during the movement along the conveyor channel from the inlet area to an outlet area in the flow direction or rotational direction of the feed wheel before the interruption area. However, a portion of the circumferentially-conveyed volume of air will not exit through an exit aperture in the exit region and be conveyed toward a combustion chamber, for example, but will remain trapped in the volumes formed between two circumferentially successive delivery vanes. The reason for this is, inter alia, that conveying blades or conveying wheel on the one hand and interruption range on the other hand are coordinated so that to avoid pressure losses between the inlet region and the outlet region, the conveyor blades with as small a distance over the substantially planar surface of the interruption range away, so that's an almost close degree the addressed volumes occurs. In these volumes, however, the air is trapped with the pressure prevailing at the outlet region, which is significantly higher than the pressure prevailing at the inlet region. When such a volume moves across the break area and the rotationally advancing volume limiting bucket sweeps the circumferential end area of the break area, such a volume opens with the gas trapped therein under pressure toward the entrance area. There is a spontaneous release of pressure, which occurs periodically with each opening of such a volume. This can lead to pressure pulsations and impairment of the delivery efficiency, but at the same time can also lead to the formation of corresponding periodic noises. Furthermore, in the case of an unfavorable geometry, the case may arise that the spontaneously relaxing air entering the inlet area from such a volume impairs the structure of the helical flow in the conveying channel.

A blower according to the preamble of claim 1 is known from DE 38 22 267 C2 This document discloses a fan with an annular channel in which the air to be delivered can enter in the region of an inlet opening. The air exits the channel in the region of an outlet opening. To the inlet area and the outlet area, an interrupting area is provided, which partially covers the inlet opening with a delimiting edge. This boundary edge is designed so that it runs approximately tangentially, so that such a vote is attained on the geometry of the delivery blades, that upon rotation of the feed wheel, the individual volumes enclosed between blades initially open in the radially outer region.

The DE 44 24 629 C1 discloses an annular channel blower in which two are provided at an angular distance of approximately 180 ° to each other arranged breaker. The suction-side end edges of these breakers are rectilinearly extending radially.

The DE 198 18 667 A1 discloses a side channel compressor in which the suction-side edge of the breaker section is curved. The radially middle edge region of the breaker is located furthest upstream. The breaker edge then continues radially inward and radially outward in the downstream direction.

The EP 0 586 934 A1 discloses a side channel blower, the breaker is concavely formed on an inlet side facing region. A radially middle region lies in the flow direction in front of the radially inner and the radially outer region.

It is the object of the present invention to develop a generic blower such that an increased conveying efficiency can be achieved.

According to the invention this object is achieved by a blower, in particular combustion air blower for a vehicle heater, according to claim 1. This comprises a blower housing, formed in the blower housing, about an axis of rotation ring-like and open on one axial side conveying channel, a feed wheel which on the Blower housing, the delivery channel on its axially open side overlapping and rotatably supported about the rotation axis and a plurality of circumferentially successive conveyor blades, which move on rotation of the impeller in a rotational direction above the conveyor channel, an inlet region with an inlet opening for the entry of conveying air into the conveying channel, lying in the rotational direction in front of the inlet region an interruption region in which the conveying channel is interrupted in the circumferential direction, wherein a lying in the direction of rotation before the inlet region Umfa ngsendbereich the interruption area is located with a radially outer portion in the rotational direction in front of a radially inner and a radially central portion, such that upon rotation of the feed wheel, a respective formed between two circumferentially immediately consecutive conveyor blades volume after sweeping the interruption area first at the radially outer region to the inlet region of the conveying channel then opens from the radially middle region and then from the radially inner region.

For such a fan according to the invention is first stated that the statement that a certain area in the direction of rotation of the feed wheel is in front of another area, means that a imaginary radial line, for example, on the feed wheel upon rotation of the feed wheel and thus upon movement of this fictitious radial line in the direction of rotation or circumferential direction first reaches the front and then the other area and thus sweeps over. In the case of the blower according to the invention, this therefore means that such a fictitious radial line, for example formed by an edge of a delivery blade lying close to the delivery channel, first sweeps over the radially outer portion of the circumferential end region of the interruption region and then upon further rotation also the radially middle and / or radially inner Section sweeps over. The consequence of this is that the volume enclosing the pressurized air will not open simultaneously over the entire radial extent of the delivery channel, but the opening of this volume will take place from radially outside to radially inside. This "gradual" or "gentle" opening has significant consequences for the operation of such a fan. First of all, the gradual opening means that a correspondingly gradual and non-sudden release of the air trapped in a volume between two delivery blades will occur, so that excessive pressure pulsations can be avoided. Furthermore, the relaxation first occurs in the radially outer region. This has the consequence that the initially still pressurized air will increasingly flow radially outside in the inlet region into the delivery channel or will flow out of the volume. The emerging under pressure from the volumes mentioned air thus receives in addition to its component of motion in the circumferential direction a spiral or Tordialströmungsrichtung communicated that the preferred entry of entering the inlet region in the conveyor channel to be conveyed air in the volumes formed between individual conveyor blades in the radially inner region and thus supports the spiral flow which is particularly important for the efficiency of the entire blower.

Further, it is provided that the peripheral end portion of the interruption portion is formed from the outer portion to the inner portion having a sickle-shaped, concavely curved contour. A further increase in the efficiency of the blower according to the invention by more efficient design of the air flow in the conveying channel is achieved in that the inlet opening is formed with respect to a radial dimension, ie radial width, of the conveying channel smaller radial dimension and that a radially inner end portion of the inlet opening in or near a radial inner end portion of the conveyor channel is located. It is preferably further provided that a circumferential dimension of the inlet opening is greater than a radial dimension of the same.

In order to make the entry of the air to be conveyed in the inlet area as free as possible, it is proposed that the circumferential end area of the interruption area in the circumferential direction does not essentially cover the inlet opening. Especially with very small fans, it may also be necessary or advantageous due to the generally required minimum circumferential length of the interruption area, which should correspond to at least the circumferential distance between two blades, when the peripheral end of the interruption area covers a front end of the inlet opening in the direction of rotation. In order to impede the entry of the air in the inlet area as little as possible even in such an embodiment, it is further proposed that at the peripheral end of the interruption area, an air entering the conveying channel is formed approximately in the direction of rotation deflecting guide surface. Here, for example, the guide surface can be curved.

Fig. 1

eine Draufsicht auf wesentliche Komponenten eines erfindungsgemäßen Gebläses;

Fig. 2

eine der Fig. 1 entsprechende Ansicht einer abgewandelten Ausgestaltungsform;

Fig. 3

eine Teil-Längsschnittansicht des in Fig. 1 gezeigten Gebläses;

Fig. 4

eine Teil-Schnittansicht des in Fig. 2 gezeigten Gebläses;

Fig. 5

eine der Fig. 1 entsprechende Ansicht einer weiteren alternativen Ausgestaltungsform des Gebläses;

Fig. 6

eine Teil-Schnittansicht des Gebläses, geschnitten längs einer Linie VI-VI in Fig. 5;

Fig. 7

eine schematische Darstellung eines alternativ ausgestalteten Förderrads.

The present invention will be described below in detail with reference to the accompanying drawings. It shows:

Fig. 1

a plan view of essential components of a blower according to the invention;

Fig. 2

one of the Fig. 1 corresponding view of a modified embodiment;

Fig. 3

a partial longitudinal sectional view of in Fig. 1 shown blower;

Fig. 4

a partial sectional view of the in Fig. 2 shown blower;

Fig. 5

one of the Fig. 1 corresponding view of another alternative embodiment of the blower;

Fig. 6

a partial sectional view of the blower, cut along one Line VI-VI in Fig. 5 ;

Fig. 7

a schematic representation of an alternative designed conveyor wheel.

In Fig. 1 and 3 a first embodiment variant of a blower 10 according to the invention is shown. This blower 10 comprises a blower housing, generally designated 12, in which a conveying passage 14 extending in an annular manner about a rotation axis A is formed. How to particular in Fig. 3 detects, this conveyor channel 14 is open on one axial side 16 of the housing 12 and thus has in its substantial circumferential extent of a semi-circular cross-sectional geometry.

The axial side 16 of the housing 12, on which the delivery channel 14 is axially open, is located opposite a feed wheel 18. This feed wheel 18 is designed substantially annular or circular disk-like and carries in its radially outer region, which is configured with a geometry corresponding geometry of the conveying channel 14, a plurality of circumferentially successive conveyor blades 20. Radial inside is the feed wheel 18 at a Shaft 22 of a drive motor 24, for example, an electric motor worn, so that upon excitation of the electric motor 24, the feed wheel 18 is in the representation of Fig. 1 in the direction of rotation R will turn.

The delivery channel 14 has an inlet region 26, in which an inlet opening 28 is formed. Through this inlet opening 28 can, as indicated by an arrow P ₁ in Fig. 3 indicated that enter to be promoted and compressed air. The inlet opening 28 is designed such that it has a radial extension which is smaller than the radial extent of the conveying channel 14. Further, the inlet opening 28 is designed with a circumferential extension which is longer than its radial extent, so that the in Fig. 1 recognizable, circumferentially elongated configuration results. Next, the inlet opening 28 in the conveyor channel 14 in Radial direction is positioned so that its radially inner end portion 30 near the radially inner end portion 32 of the conveying channel 14 is located. In the in the Fig. 1 and 3 the variant shown, the radially inner end portion 30 of the inlet opening 28 at a slight distance from the radially inner end portion 32 of the conveying channel 14. This is due to the fact that here an electric motor 24 is used, whose outer diameter is slightly larger than the minimum inner diameter of the conveying channel 14. This is also in Fig. 3 clearly visible. The geometry or positioning of the inlet opening 28 is thus predetermined so that the electric motor 24 substantially covers no areas of the inlet opening 28 and thus the air to be guided into the delivery channel 14 along the outer peripheral region of the electric motor 24 and through the inlet opening 28 in the delivery channel 14 can flow.

The passing through the inlet opening 28 into the conveying channel 14 air is taken by the circumferential movement of the conveying blades 20 for movement in the circumferential direction, so can basically move in the conveying channel 14 in the direction of rotation R. In this case, the pressure of the conveyed air increases until it finally reaches an exit region 34. The exit region 34 is separated from the entry region 26 by an interruption region, generally designated 36. This interruption area provides a surface 38 which is substantially flush with the axial side 16 of the housing 12 and which sweeps over the conveying track 20 of the conveying wheel 18 with a small axial distance. In this way, a pressure loss between the inlet region 26 and the outlet region 34 is largely prevented. From the exit region 34, an outlet opening 40 leads away below the surface 38 of the interruption region 36, in order to convey the air which has now reached the outlet region 34 under increased pressure to a system to be supplied with such air, for example the burner of a heating device.

In the circumferential movement of the feed wheel 18 is a part of the exit area 34 conveyed air on reaching this exit region 34 or when reaching the interruption range 36 in a respective enclosed between two circumferentially immediately consecutive conveyor blades 20 limited volume. Such a volume moves across the surface 38 of the interruption region 36 and the air trapped therein is initially held below the pressure prevailing at the exit region 34 without significant pressure losses. Only when such a volume or the blade advancing in the direction of rotation R moves away from the region of the interruption region 36 in the direction of rotation R, does this volume come into connection with the lower-pressure inlet region 26 and the initially trapped under pressure Air can relax. In order to avoid the occurrence of relaxation shocks by spontaneous release of the pressurized volume, according to the principles of the present invention, a circumferential end region 42 of the interruption region 40 located in front of the entrance region 26 is shaped such that a radially outer section 44 thereof projects in the direction of rotation R. a radially central portion 46 and also a radially inner portion 48 lies. This means that to a fictitious radial line L _R, which circumferentially cuts through the radially inner portion 48 of the circumferential end portion 42 at the radially inner end portion 32 of the conveying channel 14, the radially outer portion 44 has a greater distance, in opposite to the direction of rotation R, as the radially middle portion 46 and of course also the radially inner portion 48 Fig. 1 illustrated variant of the Umfangsendbereich 42 a sickle-like, convex curved contour.

The consequence of this contour or geometry of the circumferential end region 42 is that the conveying vanes 20 moving circumferentially over the circumferential end region 42 first sweep over the outer section 44, so that in the radially outer region, first of all, a connection of the initially enclosed compressed air volumes with the Entry area 26 will occur. The opening cross-section of this connection decreases due to the geometry of the peripheral end region 42 gradually, so that no spontaneous, but a gradual relaxation of the pressure can occur. Pressure pulsations can thus be largely avoided. A further consequence of this embodiment of the circumferential end region 42 and the initially occurring radially outward relaxation is that, as in Fig. 3 illustrates that emerging from the initially trapped volumes and still under pressure air primarily in the radially outer region, as indicated by an arrow P ₂ , emerge from these volumes and will enter the delivery channel 14. It can thus be seen that, based on the cross section of the conveying channel 14 and the volumes formed in the conveying wheel 18, this air flow P _{2 has} approximately the same twisting direction as the air flow P ₁ passing first through the inlet opening 28 into the conveying channel 14 and then into the region the conveying wheel 20 flowing newly introduced air. This occurs preferably and due to centrifugal force in the radially inner region in the feed wheel 18, is then due to centrifugal promoted in rotational driving radially outward, so that the significant for the efficiency of such a fan 10 helical flow is generated. The structure of this helical flow now supports the air flowing radially outward from the volumes initially enclosed above the interruption region 36. In addition to the fact that too strong compressed air pulsations can be avoided, the efficiency of the delivery and the pressure build-up can additionally be increased by the inventive design of the interruption region 36. This means that, for example, for a given delivery capacity, a smaller sized blower can be used, that with lower speed of the feed wheel 18 and thus lower energy consumption can be used and that, moreover, in addition to an increase in the entire service life and the noise level can be reduced. It is also achieved that defined operating points (defined in terms of pressure and volume) can be required at lower speeds at an increased torque. So it may possibly be an improvement in the adaptation to the optimum operating point of the engine obtained.

The increase in efficiency is still supported by the fact that the inlet opening 28 as in Fig. 1 shown dimensioned and positioned. It has been found to be particularly advantageous here that if, for example, the radial width of the delivery channel 14 near the axial side 16 of the housing 12 at 22 mm, the corresponding radial width of the inlet opening 28 in the range of between 7 and 10 mm, preferably 7.5 and 9 mm. It can be assumed, for example, of an outer diameter of the conveying channel 14 of 75 mm. That is, the ratio of the radial width of the conveying channel 14 to the radial width of the inlet opening 28 is preferably in a range of 2 to 3. Furthermore, it has proved advantageous, the circumferential extent of the inlet opening 28 in an angular range of 55 ° to 65 ° choose.

One recognizes in Fig. 1 Further, that the peripheral end portion 42 of the interruption portion 36 is positioned so that it in the circumferential direction, ie rotation direction R, the inlet opening 28 is practically not covered. Thus, the inlet opening 28 can be used with their entire opening cross-section 28 efficiently for air introduction. However, it may be necessary for structural reasons that in the circumferential direction, the inlet opening 28 and the interruption area 36 must move closer to each other. This situation is in Fig. 2 shown. Here, it can be seen that the radially inner portion 48 of the peripheral end region 22 covers at least the radially inner region of the inlet opening 28 in an end region 50 located at the front in the direction of rotation R. In the in the Fig. 2 and 4 illustrated variant, this overlap of the inlet opening 28 can be at least partially compensated by the fact that it is pulled further inward in its radially inner end portion 30, to the radially inner end portion 32 of the conveying channel 14. It thus follows the in Fig. 4 illustrated situation in which the outer circumference of the electric motor 34 extends slightly into the region of the inlet opening, but in principle the inlet opening 32 has a greater radial extent inwardly in its merging into the conveying channel 14 area. Of course Such an installation situation would be even in the case of Fig. 1 and 3 shown variant possible. In order to improve the flow conditions somewhat, it can be provided that the inlet opening 28 is formed in its entry area with a nozzle-like inlet surface 52, so that in turn an overall improvement of the flow conditions can be achieved, which is of course also in the in Fig. 1 and 3 shown variant may be the case.

If the circumferential intersection of inlet opening 28 and interruption area 36 is required to an even greater extent, an in Fig. 5 and in Fig. 6 shown variant can be selected. Here it can be seen that the end region 50 of the inlet opening 28 is relatively strongly covered, so that the central section 46 of the circumferential end region 42 also covers the inlet opening 50. In order not to impair the inflow of the air in the region of the inlet opening 28 too much here, the interruption area 36 can be provided in its circumferential end region 42 with an in Fig. 6 recognizable guide surface 54 may be formed. This, when viewed in the radial direction curved, in particular convex curved guide surface 54 ensures that the newly introduced into the region of the conveying channel 14 air flow P _{1 is} deflected in the circumferential direction and thus approximately in the direction of rotation R. The occurrence of unwanted turbulence in this inlet region 26 can thus be largely avoided.

This curved in a radial view or inclined guide surface 54 may be configured on the interruption region 36 over the entire radial extent thereof, but may also be present only where the interruption region 36, the inlet opening 28 in the circumferential direction covers. Of course, such geometry also in the in the Fig. 2 and 4 shown variant be present.

The above-described advantages in the pressure release of the trapped in the interruption area volumes can also be obtained by the fact that in principle it is ensured that these volumes initially open in a radially outer region and then in radially inner regions. This can be achieved not only by providing the previously described contour of the peripheral end region 42 of the interruption region 36, but alternatively or in conjunction therewith also by appropriate positioning of the blades, as in FIG Fig. 7 shown. When the conveyor blades are so formed or positioned in the conveyor wheel 18 that the radially outer portion extends in the circumferential direction in the radially inner region, this radially outer region, for example, on the in Fig. 1 drawn fictitious radial line L _R move in the direction of rotation R before it will do a radially middle or radially inner region. If, for example, the interruption region 36 were configured with a peripheral end region 42 which ends with the imaginary radial line L _R , then it could also be achieved that the initially trapped volumes are only opened radially outward and this opening then increases successively and also expands radially inward becomes. Of course, such a configuration or positioning of the conveyor blades with the in the Fig. 1 to 6 shown geometry of the Umfangsendbereichs 42 are combined.

Claims (6)

1. A blower, in particular a combustion air blower, for a vehicle heating device, comprising:

   - a blower housing (12),

   - a conveyor channel (14) formed in the blower housing (12), extending ringlike about a rotational axis (A) and open on an axial side (16),

   - a conveyor wheel (18) carried at the blower housing (12), covering the conveyor channel (14) at its axial open side, rotatable about the rotational axis (A) and comprising a plurality of consecutive conveyor blades (20) in circumferential direction, moving in a direction of rotation (R) above the conveyor channel (14) when the conveyor wheel (18) is rotated,

   - an entry section (26) with an entry opening (28) for the entry of air to be conveyed into the conveyor channel (14),

   - an interruptor section (36) preceding the entry section (26) in the direction of rotation (R), where the conveyor channel (14) is interrupted in the circumferential direction, with a circumferential end section (42) of the interruptor section (36) that is located upstream of the entry section (26) in the direction of rotation (R) with a radially outer section preceding a radially inner and a radially central section in the direction of rotation (R), so that when the conveyor wheel (18) rotates, a volume formed between two conveyor blades (20) directly succeeding each other in the circumferential direction, after moving over the interrupter section (36), opens first at the radially outer section towards the entry section (26) of the conveyor channel (14), then at the radially central section and then at the radially inner section,

   characterized in
   the circumferential end section (42) of the interruptor section (36) being formed from the outer section (44) to the inner section (48) with a sickle-like, concave outline, and in the entry opening (28) being designed with a smaller radial dimension in relation to a radial dimension of the conveyor channel (14) and in a radially inner end section (30) of the entry opening (28) being situated in or near a radially inner end section (32) of the conveyor channel (14).
2. A blower according to claim 1,
   characterized in a circumferential dimension of the entry opening (28) being larger than a radial dimension of the latter.
3. A blower according to claim 1 or 2,
   characterized in said circumferential end section (42) of the interruptor section (36) substantially not covering the entry opening (28) in the circumferential direction.
4. A blower according to claim 1 or 2,
   characterized in said circumferential end section (42) of the interruptor section (36) covering an end section of the entry opening (28) that is located upstream in the direction of rotation (R).
5. A blower according to claim 4,
   characterized in a guiding surface (54) being formed at the circumferential end section (42) of the interruptor section (36) redirecting the air entering the conveyor channel (14) substantially in the direction of rotation (R).
6. A blower according to claim 5,
   characterized in the guiding surface (54) being bent.

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