Note: Descriptions are shown in the official language in which they were submitted.
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BLOW-OUT GRID AND AN AIR CURTAIN DEVICE
The present invention relates to a blow-out grid and an
air curtain device.
In the art of blow-out grids and air curtain devices it
is generally known that use can be made of a blow-out grid in
a blow-out opening of the air curtain device for the purpose
of correctly guiding and orienting an airflow blown out using
the air curtain device. Use is generally made, as desired, of
a blow-out grid with longitudinal slats or of a blow-out grid
with transverse slats, depending on the consideration as to
the di.rection in which some degree of divergence is still
allowed. The choi.ce for a specific type of blow-out grid with
longitudinal slats or with transverse slats is of course also
related to the choice of a specific type of motor or fan
serving as the means for generating an airflow in the air
curtain device.
The use in air curtai.n devices of radial fans with
blades curved to the rear has for instance greatly increased
in recent times. The reason for this is that such radial fans
with blades curved to the rear have favourable properties,
particularly compared to other types of fan. This
particularly relates to favourable ratios between airflow
capacities, pressure build-up, cost, weight, sound and the
possibilities of carrying out maintenance. The present
invention is of course not limited hereto however.
Such and other known fans, which find wide use in air
curtain devices at the present time, do not have only
favourable properties. Such fans thus generate airflows with
various directional components therein. Such directional
components can be disadvantageous in respect of the final
orientation of the air curtain to be generated with the air
curtain devices. Determined parts of a passage or opening to
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be covered with the air curtain can for instance remain
uncovered by the air curtain, which thus reduces the
effectiveness of the air curtain device.
The present invention has for its object to obviate, or
at least alleviate, the above stated and other drawbacks and
imperfections of the prior art, for which purpose a blow-out
grid is provided as is defined in the appended independent
claim number 1. The use of such a blow-out grid in an air
curtain device is further defined in independent claim number
13.
With a blow-out grid according to the present invention
in an air curtain device according to the present invention
the orientation of an airflow generated by a fan in the air
curtain device can be .improved in efficient manner. By
guiding all these components in the right direction an air
curtain can be generated with the desired properties and
coverage, irrespective of the properties of the fan used in
the air curtain device.
Preferred embodiments of a blow-out grid according to
the present invention are defined in the dependent claims 2-
12. Claim 2 for instance relates to the property that the
longitudinal and the transverse slats form sets positioned
one above the other. These slats can have a mutual connection
per individual set, or the longitudinal and the transverse
slats can be mutually connected in the sets so as to provide
a unified whole. The turbulence which would result from the
longitudinal and the transverse slats all being combined in a
single height or layer, and thus having a form defining a
square in top view, can herein be avoided by providing the
longitudinal and the transverse slats in sets above each
other.
Providing a set with the transverse slats has a
favourable effect on the reduction of turbulence,
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particularly in the longitudinal direction. The intermediate
distance between the longitudinal slats can thus be made
greater or the height of the longitudinal slats can be made
smaller. Both measures can however be implemented, and it i.s
in any event the case that use of material can be minimized.
Th.e costs can hereby also be kept as low as possible.
In a further preferred embodiment the blow-out grid
according to the invention can have the feature that at least
some of the longitudinal and the transverse slats are
connected to each other in order to form a un.ified whole. By
connecting the longitudinal and transverse slats to each
other at selected positi.ons an at least one connecting bar or
rod through the slats can be omitted, which results in a
material-saving and therefore also in a saving in the
production costs of manufacturing the blow-out grid.
In yet another preferred embodiment the blow-out grid
according to the present invention has the feature that the
transverse slats have a design associated w.ith the
longitudinal divergence of the airflow other than the design
of the longi.tudinal slats associated with the transverse
divergence. The longitudinal slats can thus be designed to
guide the airflow coming from the fans in the air curtain
devices (vertically) downward in parallel manner. In the case
of some fans however, the airflow generated thereby has a
subordinate, less strong divergence in the longitudinal
direction of the blow-out grid and, in order to nevertheless
guide this subordinate, less strong component in the same
direction as the main flow using the longitudinal slats, the
transverse slats can also have a different design because
they are intended for the purpose of guiding another part of
the airflow.
In the case of the radial fans with blades curved to the
rear the longitudinal component is usually considerably
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weaker than the transverse component. It is thus possible to
suffice with fewer transverse slats in order to nevertheless
guide these longitudinal components of the airflows generated
with the fans in the desired direction.
In a further preferred embodiment a blow-out grid
according to the present invention can have the features that
the distance between the transverse slats is greater than
between the longitudinal slats. This can be related to the
"different" design of the transverse slats relative to the
design of the longitudinal slats. It is further possible that
only two transverse slats are applied, on which, or
preferably under which, the longitudinal slats are then
arranged or fixed. The transverse slats can thus serve as
suspension and as mutual connection for the longitudinal
slats. The function can then be fulfilled of the usual
connecting bars or rods, which can per se cause an annoying
turbulence, this bei.ng avoided by using the transverse slats.
The transverse slats can then also serve as suspension.
It is further possible for an embodiment of a blow-out
grid according to the present invention to have the feature
that at least one of the transverse and the longitudinal
slats have in cross-section a form adapted to the relevant
component of the airflow passing therethrough during use.
Such a form can be a curvature or an oblique position
relative to a vertical, whereby the di.rection of origin of an
airflow for guiding is related to the exit direction of this
airflow from the blow-out grid.
In a further preferred embodiment the edges of the slats
oriented in the blow-out direction are given a straight form,
i.e. transversely of the blow-out direction, against vortex
shedding and against noise nuisance. Straight can be
understood to mean that the slats can be trimmed or cut off
and thus have an angular form, from which the airflow
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separates quickly. A less favourable effect is obtained when
sai.d edges of the slats are rounded, as can result from an
extrusion process.
In a further preferred embodiment a blow-out grid
5 according to the present invention can have the feature that
at least one of the longitudinal and the transverse slats are
mutually engaging i.n order to provide a connection
therebetween. This can also be a particular feature of the
manner of mutually connecting the transverse and the
longitudinal slats, to the extent the engagement also
provides a coupling or fixing. A saving of space can hereby
also be made in the height, and therefore of the space
required for the blow-out grid.
A further preferred embodiment of a blow-out grid
according to the invention can have the feature that at least
some of the longitudinal and the transverse slats are
disposed at a distance from each other. This is a
particularly favourable embodi.ment where the available
overall hei.ght for the blow-out grid is a less critical
consideration and wherein very favourable effects are
obtained in respect of the alignment or the guiding of the
various components in the different directions of the airflow
generated with a fan. In such an embodiment said distance is
preferably substantially smaller than the width or height of
the wider or higher of the longitudinal and transverse slats.
It has been found and/or is anticipated that the desired
effects can hereby still be obtained of guiding in the
desired direction all the components of the airflow running
in different directions.
As noted above, the present invention also relates to an
air curtain device. This device then comprises a housing and
airflow-generating means in the housing. A blow-out open.ing
is further provided with an inner peripheral form, and a
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channel runs from the ai.rflow-generating means to the blow-
out opening. Then further arranged in the blow-out opening is
a blow-out grid with a peripheral form and dimens.ions
corresponding to the elongate form of this blow-out opening.
The blow-out grid is then a grid according to the present
invention and the air curtain device as a whole is thereby
also an embodiment of this invention.
In a preferred embodiment of an air curtain device
according to the present invention the airflow-generating
means are of a type which generates, at least at the pos.it.ion
of the blow-out grid, an airflow further also having a
longitudinal component as well as a transverse component. A
possible embodiment hereof can be formed by the per se known
radial fans with blades curved to the rear. The use hereof
has diverse advantages, as already stated above. An extremely
good and effectively aligned air curtain can be generated by
the combination of such radial fans with blades curved to the
rear and a blow-out grid a.ccordi.ng to the present i.nvention.
At least two radial fans with blades curved to the rear are
preferably disposed in the housing of the air curtain device
in an orientation parallel to the blow-out openi.ng and to the
blow-out grid therein. For the purpose of an effective use of
space, the channel can herein have a curvature of about 90 ,
whereby the need to align the airflows generated by such fans
is clearly apparent.
A number of embodiments of the present invention will be
described hereinbelow in more detail with reference to the
annexed drawings, in which similar or the same components,
elements and parts are designated with the same reference
numerals and in which:
fig. 1 shows a partly cut-away perspective view of an
air curtain device with a blow-out grid therein, both
according to the present invention;
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fig. 2 shows a perspective view of a part of a blow-out
grid according to the present invention;
fig. 3 shows a perspective view of another embodiment of
a part of a blow-out grid according to the present invention;
and
fig. 4 shows yet another embodiment of a part of a blow-
out grid according to the present invention;
fig. 5 shows another embodiment of a part of a blow-out
grid according to the present invention; and
fig. 6 show an alternative embodiment of a part of a
blow-out grid according to the present invention.
Fig. 1 shows an ai.r curtain device (1) in an embodiment
according to the present invention. This device comprises a
housing (2) in which fans (3) are disposed. Fans (3) are
disposed in an array parallel to a blow-out opening (4). A
blow-out grid (5) is arranged in blow-out opening (4).
A channel (6) extends between the fans (3), which are in
particular fans of the type "radial fan with blades curved to
the rear", toward the blow-out opening (4).
An airflow generated with fans (3) in the direction of
arrow A has directional components upon arrival at blow-out
opening (4) and blow-out grid (5). The main flow is
designated by arrow A. It will be apparent from fig. 1 that
the main flow, designated by arrow A, of the airflow
generated with fans (3) has a deviation relative to the
vertical direction desirable for blowing out. This is for
instance the case when the air curtain device is disposed at
a doorway or similar passage. In order to guide the mai.n flow
corresponding with arrow A vertically, longitudinal slats (7)
are arranged in blow-out grid (5). These slats are disposed
vertically, and the dimensions and intermediate distances
between the longitudinal slats (7) cause the main flow
corresponding with arrow A to be guided downward after
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passing through the curve in channel 6.
The airflow coming from the fans further also comprises
a longitudinal component which is designated by arrow B and
arrow C. Depending on the properties of the fans used,
substantially one of the two indicated longitudinal
components of arrow B and arrow C will occur, although the
occurrence of both longitudinal components of arrow B and
arrow C is not precluded.
In order to also guide the longi.tudinal components
corresponding with arrow B and arrow C in vertically downward
direction, blow-out grid (5) also comprises transverse slats
(8). Since the longitudinal components along arrow B and
arrow C in an airflow generated with fans (3) will normally
be weaker than the main flow which is indicated by arrow A
and which is substantially defined by the selection of
determined fans and the form of channel 6- in particular the
curvature therein - and the enclosure in the housing, the
intermediate distance between transverse slats (8) can be
selected to be considerably greater than the intermediate
distance between longitudinal slats (7).
Precisely in the case where fans (3) are chosen from the
type of a radial fan with blades curved to the rear, and such
fans (3) are all disposed in the same orientation, one of the
transverse components .indicated by arrow B and arrow C will
again be even stronger than the other transverse component.
In such a situation it can be favourable to adjust the
orientation or design of transverse slats (8) hereto. This
can be achieved in a design shown by way of example in fig.
2, fig. 3 or fig. 4.
Fig. 2 shows a part of a blow-out grid, the longitudinal
slats (7) of which are substantially the same as the
longitudinal slats (7) in blow-out grid (5) in fig. 1.
Transverse slats (8) are however disposed at an angle to the
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vertical. In this embodiment transverse slats (8) are
therefore oriented in relation to the origin of the
longitudinal component of the a.irflow designated by arrow B
or arrow C in fig. 1.
Fig. 3 shows a similar situation, but transverse slats
(8) here not only have an oblique position relative to the
vertical but also a curvature which is again intended to
intercept as much as possible of the longitudinal components
in an airflow and guide them downward in vertical direction.
Conversely, fig. 4 shows another embodiment wherein the
transverse slats have a substantially vertical orientation
and are simultaneously curved or have a curved surface, once
again for the purpose of maximum interception and guiding of
a transverse component of an airflow generated with fans,
depending on the origin of this airflow with such
longitudinal components therein.
The present invention is thus described in considerable
detail. Diverse additional and alternative embodiments will
occur to the skilled person, which alternative and additional
embodiments must be deemed as designs within the scope of the
present invention, as that scope is defined in the appended
claims. It is for instance possible that longitudinal slats
(7) and transverse slats (8) can be connected to each other
or fixed to each other in various ways. It is for instance
possible here to dispense with mutual connections between the
longitudinal slats, as are for instance formed in
conventional blow-out grids by means of connecting bars or
rods. This function can be fulfilled by transverse slats (8).
Such mounting tubes or bars can however also occur in
embodiments of the present invention. The transverse slats
form a set, and the same applies for the longitudinal slats.
The set with transverse slats (8) can also have many designs
other than slats extending only in transverse direction and
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substantially upright as shown in the figures and described
above. It is equally possi.ble for use to be made here of
honeycomb structures, designs defining squares and so on.
There are various embodiments, dimensions and
5 dimensioning presently provided by the inventors of the
present invention. It is for instance assumed that the
hei.ght, or at least the effective height, of the transverse
slats must be approximately as great or greater than the
i.ntermediate distance therebetween, thereby avoiding oblique
10 blow-out. The height of the longitudinal slats can for
instance amount to 50 mm, while the intermediate distance
between the longitudinal slats can amount to 20 mm. In a
possible non-limitative preferred embodiment the height of
the transverse slats can herein amount to 45 millimetres,
with an intermediate distance between the transverse slats of
about 50 mm, starting from the embodiment shown in fig. 1.
It is also possible to choose a smaller height of the
transverse slats, for instance 25 mm, in order to prevent
oblique blow-out. Transverse slats are then however required
for the purpose of downward vertical orientation of the
longitudinal component of the airflow generated by the fans.
In a possible preferred embodiment it can be the case
that the ratio (height transverse slats + height longitudinal
slats)/minus (distance between transverse slats, distance
between longitudinal slats) should be at least 5. Any other
value at which the intended effects occur can however also
result in an embodiment according to the present invention.
The grid part or set with the transverse slats also has
another favourable effect.
Providing a set with the transverse slats has a
favourable effect on the reduction of turbulence,
particularly in the longitudinal di.rection. The intermediate
distance between the longitudinal slats can thus be made
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greater, or the height of the longitudinal slats can be made
smaller. It is however possible to implement both measures,
and it is in any event the case here that use of material can
be minimized. The costs can hereby also be kept as low as
possible.
In an embodiment with a distance between the
longitudinal and the transverse slats it is provided for that
the distance may not be greater than the greatest height, at
least the greatest effective height, of the longitudinal
slats and the transverse slats. This is to prevent a decrease
in effectiveness.
In an alternative preferred embodiment according to the
invention the upper set of slats 10 is formed by a number of
straight slats (figure 5). The lower set of slats 12 is then
provided at an angle per slat so as to thereby guide the
airflow more toward the centre. In an alternative preferred
embodiment the slats of lower set 14 are formed from curved
slats (figure 6) in order to guide the airflow with reduced
resistance. The airflow is also guided in vertical direction
by the curvature, thereby reducing possible horizontal
components. If desired, it is possible to provide the lower
slats with larger d.imensions, particularly in the flow
direction, in order to thereby improve gu.iding even further.
The dimension of the overall length of the guiding of the
airflow in vertical direction herein preferably amounts to at
least five times the dimension of a(possibly partly virtual)
channel formed by the combination of slat sets. The dimension
in the direction of the airflow, in the shown embodiment the
vertical direction, can however amount to a multiple of said
factor.
It is thus the case that after examination of the
foregoing many alternat.ive and additional embodiments can
occur to the skilled person which all lie within the scope of
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the invention defined in the appended claims, unless there is
a departure therein from the actual definitions or the spirit
of the invention.
