DEVICE AND METHOD FOR BLOWING A FLUID ONTO ONE FACE OF
A THIN GLAZING ELEMENT
The present invention relates to a device for
blowing a fluid onto at least one face of a thin
glazing element.
Such a blowing device is used in the glass
industry for bending and/or toughening glazing
elements.
This device comprises, in the usual manner,
inside an enclosure having a central horizontal axis
corresponding to the central axis along which the thin
element runs, a radial-flow fan of vertical axis having
an outlet connected to at least one duct feeding at
least one blowing orifice directed onto said face and
providing a blowing width along a horizontal transverse
axis perpendicular to the vertical axis of the fan and
to the central horizontal run axis.
A device of the above type is known from
international patent application WO 02/068349.
This document states that the blowing must be
symmetrical with respect to the central horizontal run
axis and that, for this blowing to be symmetrical, the
blowing means must be placed symmetrically with respect
to the central horizontal run axis (or to the central
vertical plane).
This document thus states that two radial-flow
fans may be placed in the roof of the enclosure,
symmetrically with respect to the central vertical
plane, each fan having at least one radial feed duct
and the two ducts then being placed symmetrically with
respect to the central vertical plane.
This document also states that a single
radial-flow fan may be placed in the roof of the
enclosure but that this fan is then placed at the
center of the width of the enclosure, this fan then
having at least two radial feed ducts and these two
ducts then being placed symmetrically with respect to
the central vertical plane.
The above solution is technically satisfactory
as it does actually produce a uniform distribution of
the air flow on the surface of the thin elements
running through the enclosure, but it turns out that
this increases the cost and complicates the provision
of equipment, in particular because two different
instrumentation systems have to be provided in order to
regulate the left-hand and right-hand flows (with
respect to the central horizontal run axis) in order to
uniformly distribute the flow of air.
Another drawback of the blowing device of the
prior art lies in the fact that the heating means,
which are placed in the duct, are supported by side
walls of the enclosure. It is then difficult to remove
these means, so as especially to clean them or to
inspect them.
The prior art also teaches, in patent
application JP 2005097033, a blowing device according
to the preamble of claim 1. In this device, the
vertical axis of the fan is sometimes shifted along the
central horizontal axis of the enclosure (cf. figures
9d - 9f of that document), but the vertical axis of the
fan is still centered with respect to the blowing width
bounded by the blowing orifice.
Moreover, the prior art teaches, from patent
application DE 42 19 003, a blowing device according to
the preamble of claim 1 in which the vertical axis of
the fan is shifted with respect to the central
horizontal axis of the enclosure in such a way that
this vertical axis of the fan is at the boundary of the
blowing width bounded by the blowing orifice, or even
outside this blowing width.
The object of the invention is to alleviate the
drawbacks of the prior art by proposing a blowing
system that enables the flow of air to be uniformly
distributed, as previously, but having fewer means and
fewer instruments, and being thus less expensive.
The present invention thus relates in its
widest sense to a device for blowing a fluid onto at
least one face of a thin glazing element as claimed in
claim 1.
This device comprises, inside an enclosure
having a central horizontal axis corresponding to the
central axis along which the thin element runs, a
radial-flow fan of vertical axis having an outlet
connected to at least one duct feeding at least one
blowing orifice directed onto said face and providing a
blowing width along a horizontal transverse axis
perpendicular to the vertical axis of the fan and
perpendicular to the central horizontal run axis.
This device is noteworthy in that it includes a
single fan in each vertical plane comprising the
vertical axis of the fan and perpendicular to the
central horizontal axis and in that the vertical axis
of the fan is placed at a distance 5 from the central
horizontal axis which is between 25% and 42.5% of this
blowing width, i.e. at a distance between one quarter
and one seventh of this blowing width, starting from
the central horizontal axis.
The duct that joins the outlet of the fan to
the blowing orifice is essentially directed so as to be
transverse to the central run axis.
Furthermore, in this device, the vertical axis
of said fan is preferably placed at a distance from the
central horizontal axis equal to around one third (±
5%) of the blowing width.
Heating means are placed in said duct and are
preferably supported by the roof of said enclosure,
just like the fan, so as to facilitate their
maintenance. They may be separated from the enclosure
and raised, for example using a hoist or lifting gear.
Moreover, this avoids having to have electrical cables
or connections on the external lateral faces of the
device.
The device according to the invention also
comprises at least one blowing orifice preferably
comprising a plate having, in cross section along the
central horizontal axis, substantially the form of a
double U, this plate having a plurality of holes
located on the bottom of the Us. These holes are
directed approximately vertically, that is to say
perpendicular to the main surface of the thin element
to be heated.
Preferably, the two Us are joined by a plate
element in the form of an inverted V.
The present invention also relates to a
toughening furnace as claimed in claim 6, this furnace
comprising several blowing devices according to the
invention, these devices being aligned so that their
central horizontal axes coincide.
All the fans of the blowing devices are then
preferably placed on the same side of the common
central horizontal axis, so as to facilitate
maintenance.
The present invention does not apply solely to
flat thin elements but also to curved elements. It may
in particular be used for toughening monolithic glass
panes.
The present invention also relates to a blowing
method as claimed in claim 8, employing in particular
the device according to the invention, in which the
blowing is carried out onto at least one face of a thin
glazing element, the thin element running inside an
enclosure along a central horizontal axis, a radial-
flow fan of. vertical axis having an outlet connected to
at least one duct feeding at least one blowing orifice
directed onto said face and providing a blowing width
along a horizontal transverse axis perpendicular to the
vertical axis of the fan and to the central horizontal
run axis.
This method of blowing a fluid is noteworthy in
that a single fan in each vertical plane comprising the
vertical axis of the fan and perpendicular to the
central horizontal axis is blowing and in that the
vertical axis of said fan is placed at a distance from
the central horizontal axis which is between 25% and
42.5% of this blowing width.
Advantageously, the device and the method
according to the invention thus provide a uniform
distribution of the air flow on the surface of the thin
elements using a single fan and a single heating means.
Also advantageously, this heating means is
placed in the upper part of the enclosure (in the roof)
and is thus easy to access.
Also advantageously, the cost of the device and
its weight are reduced because fewer means are required
to produce the hot air flow (less sheet metal to
produce the ducts, less instrumentation for regulating
the two sides of the blowing).
Finally, the operation of the device is
advantageously simplified and it is even also possible
to manage the heating better and to eliminate the
appearance of hot spots in the roof.
The present invention will be better understood
on reading the following detailed description of
nonlimiting exemplary embodiments and on examining the
appended figures in which:
• figure 1 illustrates a partial longitudinal
sectional view in a longitudinal plane passing through
the rotation axis of a fan of a blowing device
according to the invention;
• figure 2 illustrates a transverse sectional
view along AA of figure 1, in the plane P comprising
the vertical axis of the fan and perpendicular to the
horizontal central run axis;
• figure 3 illustrates a top view of a blowing
device according to the invention; and
• figure 4 illustrates a detailed sectional
view of a blowing orifice.
It should be pointed out that in these figures
the proportions of the various elements shown have not
been strictly respected and that the section elements
in the plane or in the background are not always shown,
so as to make it easier to examine them.
Figure 1 illustrates a partial longitudinal
sectional view of a toughening furnace according to the
invention, comprising three devices 1 for blowing a
fluid, in this case air, onto at least one face of a
thin glazing element 7 (only a single device being
shown in section, the first in the run direction of the
thin element), these devices 1 being positioned one
after another along a central horizontal axis XX'
corresponding to the central axis along which the thin
element runs through the three devices.
The thin element 7 has been shown in the second
blowing device for the sake of clarity. It enters the
furnace via the left of the figure and emerges
therefrom via the right.
The thin element 7 is moved perpendicular to
the plane of section along mutually parallel rollers 8,
of any type known per se, for example having a diameter
of 10 cm. These rollers each have a transverse
horizontal rotating spindle, perpendicular to the
central horizontal axis XX', these spindles being
rotated by a single drive means of the chain or belt
type and these spindles being separated from one
another by a spacing s of 12 cm for example.
Each blowing device 1 or unit (or module)
includes, inside an enclosure 2, a single fan 3. This
fan is placed vertically in such a way that the
rotation axis of the elements producing the flow of air
is vertical, along a vertical axis VV. The flow of air
produced by the fan is a radial flow, that is to say it
extends, at the outlet of the fan, in a centripetal
horizontal direction with respect to the rotation axis
of the fan.
This radial flow is channeled by means of a
duct 51 joined to the fan 3 and extending approximately
horizontally, this duct 51 feeding six blowing orifices
43 of inverted funnel shape, all directed onto the
rollers 8 that support and transport the thin element
7.
Placed between the fan 3 and the blowing
orifices 43 are heating means 6 comprising electrical
resistance elements in contact with fins 66 extending
vertically inside the duct 51.
These heating means 6 are thus supported by the
roof of the enclosure 2.
The blowing orifice 43 thus blows hot air over
a blowing width 1, here about 2.4 m, which can be seen
in figure 2, corresponding approximately to 95% of the
internal width of the enclosure, this width being
considered along a horizontal transverse axis YY'
perpendicular to the axes XX' and VV .
The enclosure 2 of each of the three blowing
devices is parallelepipedal and the three enclosures 2
are placed one beside the other. The outlet orifice via
which the thin element 7 emerges from the first blowing
device thus corresponds to the inlet orifice via which
the thin element 7 enters the second blowing device,
considering the direction in which the thin element
runs through the furnace, and the outlet orifice via
which the thin element 7 emerges from the second
blowing device thus corresponds to the inlet orifice
via which the thin element 7 enters the third blowing
device, again considering the direction in which the
thin element runs through the furnace.
The wall of the enclosure 2 comprises four
plates made of ceramic-fiber insulating material.
According to the embodiment of the invention
illustrated, the lower boundary of the enclosure 2 is
formed by the set of rollers 8 that support and
transport the thin element 7. This set of rollers thus
forms part of the floor of the furnace.
The internal height h of the enclosure, from
the spindles of the rollers 8 to the underside of the
roof, is of the order of 1 meter and the thickness e of
the roof is of the order of 30 cm. The total height of
the enclosure, from the spindles of the rollers 8 to
the top of the roof, is thus of the order of 1.3
meters, which is small.
The total length L of the furnace is of the
order of 5 meters, each blowing device having a length
L' of about 1.8 meters in the case of the first and
third devices and a length I/' of about 1.5 meters in
the case of the second device.
Each blowing device 1 comprises a single fan 3
in a vertical plane P comprising the vertical axis VV
of the fan, parallel to the axis YY' and perpendicular
to the axis XX'.
As may be seen in figures 2 and 3, the vertical
axis VV' of the fan is placed at a distance d here of
about 80 cm from the central horizontal axis XX', i.e.
at a distance of one third of the blowing width 1.
This distance d between the vertical axis VV
of a fan and the central horizontal axis XX' is not
necessarily the same for the three blowing devices, but
it is always between 25% and 42.5% of the blowing width
1.
The blowing width here is measured in the plane
P comprising the axis VV. It is in fact slightly less
than the internal width of the enclosure, which is here
about 2.5 meters.
Each blowing orifice 43 consists of an inverted
funnel having straight walls, the lower end of which is
provided with nozzles 10, these nozzles being placed in
pairs along the longitudinal direction of the blowing
device and are illustrated in detail in figure 4. The
distance along the longitudinal direction between two
nozzles is identical to the spacing s between the
rollers 8, and the nozzles are also aligned
transversely so as to be positioned exactly above the
rollers.
The blowing orifice has, in the bottom part,
above the rollers 8, a plate 44 substantially in the
form of a double U in cross section along the
longitudinal axis of the device and provided at the
bottom of the Us with holes 45 each having a diameter
of about 5 mm, so as to allow the flow of air to emerge
from the orifice toward the face of the thin element.
The distance along the longitudinal direction between
the vertical axes of two adjacent holes 45 is about
12 nun. The distance between two adjacent holes along
the transverse direction is also about 12 mm. As can be
seen in figure 4, the two Us are joined by a plate
element that is not flat but in the form of an inverted
V, so as to help to guide the flow of air toward the
holes.
The inlet of each funnel is shifted to the
lateral end of the blowing width relative to the
central horizontal axis XX'.
The fluid jets expelled from the nozzles 10
directed toward the thin element 7 are contained in
"transverse" vertical planes, i.e. those perpendicular
to the central horizontal longitudinal axis XX'.
Moreover, the nozzles 10 may have, over the
width of the enclosure, a relatively large overlap
region. In figures 1 and 2, this overlap region is
approximately equal to the total width of the enclosure
2. This arrangement is chosen so as to guarantee
greater uniformity.
A smaller overlap region may of course be
provided without thereby departing from the scope of
the present invention.
The general movement of the fluid inside the
enclosure 2 is as indicated by the double arrows in
figures 1, 2 and 4.
This movement, which is unsymmetrical with
respect to the central vertical axis ZZ' of each
blowing device, does however distribute the fluid
optimally and uniformly over the surface to be treated.
Moreover, the arrangement of the various
constituents, in particular the fans 3 and the heating
means 6, ensure that there is easy reliable access in
case of repair and/or for maintenance.
In the toughening furnace illustrated, all the
fans 3 are placed on the same side of the central
horizontal axis XX'.
When the enclosure comprises several fans 3, it
is also envisioned to provide means for separately
adjusting and controlling the temperature and/or the
flow rate of the fluid output by each of the fans. Any
means known per se may be used for this function.
Thus, particular appropriate temperature
profiles at the point where the air is blown onto the
means for transporting the thin elements are obtained.
This modular feature is highly appreciated by users.
Furthermore, the subject of the invention is a
blowing/heating unit comprising either a device as
described above on each face of the thin element or one
device described above that blows onto one face,
combined with another blowing and/or heating means of
radiative or convective type on the other face.
Moreover, it is possible to produce a heat
treatment furnace with a single blowing device 1
according to the invention or with only two devices, or
even with more than three blowing devices.
The present invention thus makes it possible to
provide a modular furnace, the various modules (blowing
devices) of which may be aligned so that their central
horizontal axes XX' coincide.
It would be conceivable to provide several
radial-flow fans inside a single blowing device,
provided that they are positioned along the horizontal
central axis so that a single radial-flow fan is placed
in each vertical plane comprising the vertical axis of
the fan and perpendicular to the central horizontal
axis.
However, within the context of the invention,
it is preferred to provide a plurality of blowing
devices aligned so that their central horizontal axes
XX' coincide, each blowing device having only a single
radial-flow fan, this fan being the only one placed in
a vertical plane comprising the vertical axis of the
fan and perpendicular to the central horizontal axis.
With this solution, adjustments are facilitated by the
fact that a flow output by a fan cannot disturb the
flow output by another fan inside a blowing device.
The present invention has been described in the
foregoing by way of example. Of course, a person
skilled in the art is capable of producing various
alternative embodiments of the invention without
thereby departing from the scope of the patent as
defined by the claims.
We claim:
1. A device (1) for blowing a fluid onto at least
one face of a thin glazing element (7), the device
comprising, inside an enclosure (2) having a central
horizontal axis (XX') corresponding to the central axis
along which the thin element (7) runs, a radial-flow
fan (3) of vertical axis (VV) having an outlet
connected to at least one duct (51) feeding at least
one blowing orifice (43) directed onto said face and
providing a blowing width 1 along a horizontal
transverse axis (YY' ) perpendicular to the axes (XX' )
and (VV ) , characterized in that it includes a single
fan (3) in each vertical plane P comprising the
vertical axis (VV) and perpendicular to the central
horizontal axis (XX' ) and in that the vertical axis
(VV ) of said fan is placed at a distance d from the
central horizontal axis (XX') which is between 25% and
42.5% of this blowing width 1.
2. The device (1) as claimed in claim 1,
characterized in that the vertical axis (VV ) of said
fan (3) is placed at a distance d from the central
horizontal axis (XX') equal to around one third of the
blowing width 1.
3. The device (1) as claimed in claim 1 or claim
2, characterized in that heating means (6) are placed
in said duct (51) and are supported by the roof of said
enclosure (2) .
4. The device (1) as claimed in any one of the
preceding claims, characterized in that it comprises at
least one blowing orifice (43) comprising a plate (44)
having, in cross section along the central horizontal
axis (XX' ) , substantially the form of a double U, this
plate having a plurality of holes (45) located on the
bottom of the Us.
5. The device (1) as claimed in the preceding
claim, characterized in that the two Us are joined by a
plate element in the form of an inverted V.
6. A toughening furnace, comprising several
blowing devices (1) as claimed in any one of the
preceding claims, the devices being aligned so that
their central horizontal axes (XX') coincide.
7. The toughening furnace as claimed in the
preceding claim, characterized in that all the fans (3)
of the devices (1) are placed on the same side of the
common central horizontal axis (XX').
8. A method of blowing a fluid onto at least one
face of a thin glazing element (7), the thin element
(7) running inside an enclosure (2) along a central
horizontal axis (XX'), a radial-flow fan (3) of
vertical axis (W ) having an outlet connected to at
least one duct (51) feeding at least one blowing
orifice (43) directed onto said face and providing a
blowing width 1 along a horizontal transverse axis
(YY') perpendicular to the axes (XX') and (VV),
characterized in that a single fan (3) in each vertical
plane P comprising the vertical axis (W ) and
perpendicular to the central horizontal axis (XX') is
blowing and in that the vertical axis (VV) of said fan
is placed at a distance d from the central horizontal
axis (XX') which is between 25% and 42.5% of this
blowing width 1.

The invention relates to a device (1) for
blowing a fluid onto at least one face of a thin
glazing element, the device comprising, inside an
enclosure (2) having a central horizontal axis (XX')
corresponding to the central axis along which the thin
element (7) runs, a single radial-flow fan (3) in each
vertical plane P comprising the vertical rotation axis
(VV') of the fan and perpendicular to the central
horizontal axis (XX' ) , the vertical axis (VV ) of said
fan being placed at a distance d from the central
horizontal axis (XX') which is between 25% and 42.5% of
the blowing width 1.