U.S. patent application number 14/403807 was filed with the patent office on 2015-05-28 for ventilation unit.
The applicant listed for this patent is SPAL AUTOMOTIVE S.r.l.. Invention is credited to Pietro DeFilippis.
Application Number | 20150147167 14/403807 |
Document ID | / |
Family ID | 46582775 |
Filed Date | 2015-05-28 |
United States Patent
Application |
20150147167 |
Kind Code |
A1 |
DeFilippis; Pietro |
May 28, 2015 |
VENTILATION UNIT
Abstract
A ventilation unit for generating an air flow comprises a
centrifugal rotor able to rotate about an axis of rotation, a
diffuser comprising a first and a second outlet, the outlets being
positioned on opposite sides of the centrifugal rotor and
delimiting a blowing duct; the centrifugal rotor is inserted in the
blowing duct and is aligned with the first outlet and with the
second outlet according to a main axis which is perpendicular to
the axis of rotation.
Inventors: |
DeFilippis; Pietro; (Varazze
(Savona), IT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SPAL AUTOMOTIVE S.r.l. |
Correggio (Reggio Emilia) |
|
IT |
|
|
Family ID: |
46582775 |
Appl. No.: |
14/403807 |
Filed: |
May 30, 2013 |
PCT Filed: |
May 30, 2013 |
PCT NO: |
PCT/IB2013/054473 |
371 Date: |
November 25, 2014 |
Current U.S.
Class: |
415/206 ;
454/249 |
Current CPC
Class: |
F24F 7/08 20130101; F04D
29/44 20130101; F04D 29/4246 20130101 |
Class at
Publication: |
415/206 ;
454/249 |
International
Class: |
F04D 29/42 20060101
F04D029/42; F04D 29/44 20060101 F04D029/44; F24F 7/08 20060101
F24F007/08 |
Foreign Application Data
Date |
Code |
Application Number |
May 31, 2012 |
IT |
BO2012A000298 |
Claims
1. A ventilation unit for generating an air flow comprising a
centrifugal rotor able to rotate about an axis of rotation, a
diffuser associated with the centrifugal rotor, comprising a first
and a second outlet, the outlets being positioned on opposite sides
of the centrifugal rotor and delimiting a flow blowing duct, the
centrifugal rotor being inserted in the blowing duct, said
ventilation unit being characterised in that the centrifugal rotor,
the first outlet and the second outlet are aligned with each other
according to a main axis which is perpendicular to the axis of
rotation.
2. The ventilation unit according to claim 1, wherein the diffuser
comprises means for guiding the air flow in the blowing duct, said
guide means operating between the centrifugal rotor and the first
outlet and/or between the centrifugal rotor and the second
outlet.
3. The ventilation unit according to claim 2, wherein the guide
means comprise a first flow diverter, forming a first narrowing in
the duct, positioned in said blowing duct between the rotor and the
first outlet, and a second flow diverter forming a second narrowing
in the duct and positioned in the blowing duct between the rotor
and the second outlet, said first and second flow diverters being
positioned on opposite sides of the rotor.
4. The ventilation unit according to claim 3, wherein the first and
second flow diverters each have a first face which is curved, with
the concavity facing towards the rotor.
5. The ventilation unit according to claim 4, wherein the first
face of the first and second flow diverters is formed by a portion
of a cylindrical surface having a main axis which coincides with
the axis of rotation.
6. The ventilation unit according to claim 3, wherein the first and
second flow diverters each comprise a second face which is curved,
with the concavity respectively facing towards the first outlet and
towards the second outlet, and a cusp connecting the first face and
the second face.
7. The ventilation unit according to claim 3, wherein the rotor is
of the radial type with vanes having tips pointing backwards, said
first and second flow diverters being positioned in the blowing
duct in such a way that during generation of the air flow said tips
encounter, one after another, the first flow diverter, the second
narrowing, the second flow diverter and the first narrowing.
8. The ventilation unit according to claim 1, wherein the diffuser
has a central symmetry, the centre of symmetry belonging to the
axis of rotation.
Description
TECHNICAL FIELD
[0001] This invention relates to a ventilation unit and in
particular a ventilation unit comprising a centrifugal fan, more
specifically a radial fan, which is housed in a corresponding
diffuser.
BACKGROUND ART
[0002] Radial fans are fans of a substantially known type which,
when driven to rotate suck air from an intake which is coaxial with
the axis of rotation and generate an air flow which is spread
radially from the fan itself.
[0003] Such fans are usually inserted, together with a respective
motor, in diffusers which are suitably shaped for directing and
optimising the air flow generated by the fan.
[0004] In general the fans described above are used in the
automotive sector, for example in cars, lorries, agricultural
machinery, earth moving machinery, buses and the like, for carrying
heat away from heat exchangers, for moving air in driver and
passenger compartments or, in general, for cooling components or
parts which are subject to temperature increases during
operation.
[0005] Recently there has been a particular need, in vehicles
powered also or exclusively by electricity, for cooling the energy
storage batteries.
[0006] In this particular application, prior art fans were
developed to obtain low noise emissions accompanied by high fluid
dynamic efficiency in relatively limited dimensions, but
satisfactory results were not achieved.
DISCLOSURE OF THE INVENTION
[0007] In this context, the main aim of this invention is to
overcome the above-mentioned disadvantages
[0008] One aim of this invention is to provide a ventilation unit,
intended in particular for cooling batteries, which is more
efficient than the prior art solutions.
[0009] A further aim is to provide a ventilation unit which has
lower noise emissions than the prior art solutions.
[0010] The technical purpose indicated and the aims specified are
substantially achieved by a ventilation unit according to claim
1.
BRIEF DESCRIPTION OF DRAWINGS
[0011] Further features and advantages of this invention are more
apparent from the non-limiting description which follows of a
preferred, non-limiting embodiment of a ventilation unit as
illustrated in the accompanying drawings, in which:
[0012] FIG. 1 is a partly exploded schematic perspective view of a
ventilation unit according to this invention;
[0013] FIG. 2 is a schematic side view of the ventilation unit of
FIG. 1;
[0014] FIG. 3 is a cross-section of the ventilation unit according
to line III-III of FIG. 2;
[0015] FIG. 4 illustrates a fluid dynamic simulation of operation
of a ventilation unit according to this invention
[0016] FIG. 5 illustrates a second fluid dynamic simulation of
operation of a ventilation unit according to this invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE
INVENTION
[0017] With reference to the accompanying drawings, the numeral 1
denotes a ventilation unit according to this invention, which is
intended to generate a cooling air flow F.
[0018] The ventilation unit 1 comprises a centrifugal rotor 2, in
particular radial, having an external diameter D and able to rotate
about an axis R of rotation, means for operating the rotor 2, of
the substantially known type and schematically illustrated with a
block 3, and a diffuser 4 for supporting the rotor 2.
[0019] The rotor 2, only described as regards those parts necessary
for an understanding of this invention, comprises a hub 2a and a
plurality of vanes 2b, with tips 2c, which are connected to the hub
2a.
[0020] The diffuser 4 extends according to a plane P which is
perpendicular to the axis R of rotation and delimits a blowing duct
5 in which the rotor 2 is inserted.
[0021] The diffuser comprises an inlet 20 and a first and a second
outlet 6, 7 for the air flow F.
[0022] The first and second outlets 6, 7 are positioned on opposite
sides of the rotor 2.
[0023] As illustrated, the first and second outlets 6, 7 are
positioned on opposite sides of the inlet 20 of the diffuser 4.
[0024] The centrifugal rotor 2, the first outlet 6 and the second
outlet 7 are aligned with each other according to a main axis X
which is perpendicular to the axis R of rotation.
[0025] The inlet 20 of the diffuser 4 corresponds, preferably, to
an inlet of the rotor 2.
[0026] The inlet 20 of the diffuser 4 extends in a plane
transversal to, preferably perpendicular to, the axis R of
rotation.
[0027] The axis X also defines a blowing direction of the
ventilation unit 1 which, in the example illustrated, corresponds
to the main direction of extension of the diffuser 4.
[0028] The axis R of rotation defines a preferred flow direction of
the air entering the rotor 2 and the diffuser 4.
[0029] The air flow F exits the duct 5 along the blowing line in a
direction V1 from the outlet 6 and exits in a direction V2,
opposite to V1 from the outlet 7.
[0030] In other words, the diffuser 4 and the rotor 2 are assembled
and configured relative to each other in such a way that the flow
generated by the rotor 2 is distributed in the directions V1 and V2
of the blowing line parallel with the main axis X.
[0031] The diffuser 4 advantageously has a structure with central
symmetry, the centre being at the axis R of rotation.
[0032] In other words, considering a section parallel with the
plane P, perpendicular to the axis R, the axis R itself defines at
the intersection with the above-mentioned section the centre of
symmetry of the section considered.
[0033] In that way, the flow F remains divided in a balanced way in
terms of flow rate between the two outlets 6, 7.
[0034] In the example illustrated the diffuser 4 has the shape of a
parallelepiped, in particular a right-angled parallelepiped,
comprising an upper face 8, a lower face 9, a first and a second
side face 10, 11 while the outlets 6, 7 define the remaining two
faces of the diffuser 4.
[0035] The first and second outlets 6, 7 respectively delimit a
first and a second outfeed section 6a, 7a for the flow F.
[0036] In the embodiment described by way of example, the inlet 20
of the diffuser 4 is provided on the face 8.
[0037] The first and second outfeed sections 6a, 7a are transversal
to the axis X and in particular are perpendicular to it.
[0038] Moreover, preferably, the first and second outlets 6, 7 are
positioned at the same height, measured along the axis R of
rotation.
[0039] Preferably, the outlets 6, 7 are identical and are
positioned symmetrically relative to the rotor 2.
[0040] Looking at the rotor 2 in more detail, it may be seen how
advantageously the height of the rotor, measured along the axis R,
is comparable with the height of the duct 5, measured along the
axis R.
[0041] With reference in particular to FIGS. 3, 4 and 5, it can be
seen how the rotor 2 is of the radial type with vanes 2b having
tips 2c pointing backwards. In that case, in the figures indicated,
the direction V3 of rotation is anti-clockwise.
[0042] in the solution illustrated in FIGS. 1, 2, 3 and 5, the
diffuser 4 comprises means for guiding the above-mentioned air flow
F inside the duct 5.
[0043] The flow guide means are positioned in the diffuser between
the rotor 2 and the first outlet 6 and between the rotor 2 and the
second outlet 7, for guiding the flow F inside the duct 5.
[0044] More precisely, in the example embodiment illustrated, the
guide means comprise a first flow diverter 12, positioned in the
blowing duct 5 between the rotor 2 and the first outlet 6, which
delimits a narrowing 13 in the duct 5.
[0045] The guide means also comprise a second flow diverter 14,
positioned in the blowing duct 5 between the rotor 2 and the second
outlet 7, which delimits a second narrowing 15 in the duct 5.
[0046] The first flow diverter 12 and the corresponding narrowing
13 and the second flow diverter 12 with the corresponding narrowing
14 are positioned on opposite sides of the rotor 2 along the axis
X.
[0047] The first flow diverter 12 and the corresponding narrowing
13 and the second flow diverter 14 with the corresponding narrowing
15 are positioned on opposite sides of the rotor 2 along a
transversal axis Y which is perpendicular to the blowing line and
to the axis R of rotation.
[0048] The axis R of rotation, the main axis X and the transversal
axis Y define a set of three axes which are at tight angles to each
other.
[0049] Preferably, the diffuser 4 has a structure with central
symmetry, the centre being at the axis R of rotation.
[0050] In other words, considering a section parallel with the
plane P, perpendicular to the axis R, the axis R itself defines at
the intersection with the above-mentioned section the centre of
symmetry of the section considered.
[0051] As illustrated, since the rotor 2 is of the radial type with
vanes having tips pointing backwards and able to rotate in an
anti-clockwise direction V3 in the example figures, the first flow
diverter 12 and the second flow diverter 14 are positioned in the
duct 5 in such a way that, in practice, given a vane 2b the tip 2c
of the vane encounters, during air flow F generation, first the
first flow diverter 12 followed by the second narrowing 15, then
the second flow diverter 14 and finally, before encountering the
first flow diverter 12 again, it encounters the first narrowing
13.
[0052] In that way, as is described in more detail below, the flow
F is optimised in terms of noise and efficiency.
[0053] In the example illustrated, the first and second side faces
10, 11 of the diffuser 4, that is to say, the walls which define
them, are shaped in such a way as to create, inside the duct 5, the
flow diverters 12 and 14 which project towards the inside of the
duct 5.
[0054] In further embodiments, the faces 10, 11 are fiat and the
flow diverters 12, 14 project from them towards the inside of the
duct 5.
[0055] Again in this embodiment, equipped with flow diverters 12.
14 for guiding the flow F, as indicated the diffuser 4 maintains a
central symmetry, the centre being at the axis R of rotation.
[0056] The first and second flow diverters 12, 14 have a similar
shape and profile and each comprises a respective first face 12a,
14a which is curved, with the concavity facing towards the rotor
2.
[0057] Its first face 12a, 14a is formed by a portion of a
cylindrical surface whose main axis coincides with the axis R of
rotation.
[0058] Advantageously, as also illustrated in FIG. 5, the faces
12a, 14a, which are defined by a portion of cylindrical surface,
convey the flow exiting the rotor 2 towards the outlets 7 and 6,
following its natural rotational pattern.
[0059] In that way, the diffuser 4 is particularly efficient in
conveying the flow F exiting the rotor 2 towards the outlets 7 and
6.
[0060] Preferably, the faces 12a, 14a extend towards the outlet 7
and the outlet 6, respectively, with a stretch or profile 12d,
14d.
[0061] The stretches 12d and 14d are each preferably defined by a
flat surface lying in the plane defined by the axes R and X.
[0062] The first and second flow diverters 12, 14 each have a
respective second face 12b, 14b which is curved, with the concavity
respectively facing towards the first outlet 6 and towards the
second outlet 7.
[0063] The first and second flow diverters 12, 14 each have a cusp,
that is to say, a rounded point, 12c, 14c, connecting the first
face 12a, 14a and the second face 12b, 14b.
[0064] Given the diameter "D" of the rotor 2 and the width "H" of
the duct 5 (measured along the axis Y), starting from the
corresponding wall of the diffuser 4 the height "h", measured along
the axis Y, of the cusps 12c and 14c is a function of "H" and "D",
that is to say, h=.quadrature.(H;D).
[0065] Similarly, the distance "I" of the cusps 12c, 14c from the
axis R of rotation, measured along the axis X, is a function of "H"
and "D", that is to say, I=.quadrature.(H;D).
[0066] The functions of "H" and "D" indicated above are also
weighted based on the rotor 2 speed of rotation.
[0067] The guide means 12, 14 allow the recovery of dissipated
energy which would otherwise be lost in the generation of
vortices.
[0068] In FIG. 4, showing the basic embodiment of the diffuser 4,
the numeral 16 denotes recirculations in the flow F.
[0069] FIG. 5 shows how the recirculations are absent in the
embodiment of the ventilation unit 1 comprising the flow diverters
12, 14, under the same operating conditions.
[0070] Advantageously, the presence of the flow diverters 12, 14
causes an increase in performance, even compared with the first
embodiment illustrated in FIG. 4, without compromising the output
flow rate from the ventilation unit 1. Moreover, the flow F remains
divided in a balanced way in terms of flow rate between the two
outlets 6, 7.
[0071] Advantageously, elimination of the recirculations 16
contributes to a reduction in the overall noise of the ventilation
unit 1.
[0072] In general, the central symmetry of the ventilation unit 1
allows the flow F to be rendered uniform in all portions of the
diffuser 4.
[0073] As indicated, the positioning of the flow diverters 12, 14
in the duct 5 is determined depending on the dimensions of the
rotor 2 and the speed of rotation of the rotor.
[0074] The position "I" according to the axis X of the flow
diverters 12, 14 depends on the flow rate and the speed of rotation
of the rotor 2, like the height "h" of the flow diverters relative
to the corresponding wall of the diffuser.
* * * * *