Note: Descriptions are shown in the official language in which they were submitted.
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AIR CURTAIN DEVICE AND METHOD FOR REALIZING A HORIZONTAL AIR
CURTAIN WITH ADDITIONAL AIRFLOW
The present invention relates to an air curtain device for
realizing an air curtain. The invention more particularly
relates to an air curtain with a substantially horizontal
airflow. Such an air curtain device is usually provided in or
close to an opening, in particular a door opening.
Known air curtain devices are usually horizontally placed
devices which in use realize an air curtain flowing in vertical
direction. These known devices require an installation space at
the top and/or bottom of the opening where an air curtain has
to be realized. Since sufficient space for installation is not
always available, air curtains are also known which are provided
on a side of the opening. During use these air curtain devices
disposed in vertical direction realize an air curtain flowing
in horizontal direction. These air curtains are found to be
inefficient in practice, resulting in a relatively high energy
consumption. In addition, use has to be made of relatively strong
airf lows in order to realize an air curtain, whereby the comfort
for persons passing through the air curtain is not optimal
either.
The present invention has for its object to provide an air
curtain device for realizing a horizontal air curtain which
realizes such an air curtain in a more efficient manner and wholly
or partially obviates the above stated drawbacks.
The present invention provides for this purpose an air
curtain device for realizing a horizontal air curtain, the air
curtain device comprising:
- a housing with air displacing means;
- at least one air inlet for supplying air to the housing;
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- a first outflow opening for realizing the horizontal air
curtain in a first direction; and
- a second outflow opening for realizing an additional
airflow in a second direction during use, wherein the air
curtain and the additional airflow are provided at an angle
to each other.
The air curtain device according to the invention comprises
a housing with air displacing means therein, comprising for
instance one or more fans. Air is supplied via an air inlet. In
most cases this air inlet is situated in the immediate vicinity
of the position where the air curtain is realized in use, although
the air inlet can also be provided at other positions at which
the air is transported to the desired position. If desired, a
plurality of air inlets can also be provided.
The device realizes the air curtain flowing substantially
in a horizontal direction using a first outflow opening or first
series of outflow openings. This outflow opening or series of
outflow openings extends substantially in a vertical direction,
usually over substantially the same height as the opening in
which an air curtain is provided. An air curtain is provided in
or close to an opening in a wall, wherein the opening is usually
a door opening, for instance the entrance to a shop or storage
space. The air curtain device according to the invention is
further provided with a second outflow opening or a second series
of outflow openings for realizing an additional airflow during
use. This additional airflow is provided at an angle to the actual
air curtain realized in the opening during use. Providing the
two airf lows at an angle also means in respect of the air curtain
device according to the invention that the two airflows also
extend over a substantially corresponding height. The effective
height of the two airf lows is therefore preferably substantially
the same in the vertical direction.
Vertically placed air curtain devices are in practice
usually placed in front of the wall at some distance therefrom,
adjacently of the opening, so as not to make the opening or
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passageway smaller. In use the air curtain extends substantially
in or parallel to the opening in the. wall. This results in
practice in leakage loss between the air curtain device and the
wall, since the air curtain device is not provided in the opening
itself. By providing the additional airflow, which is oriented
during use at least partially toward the wall, a screening is
brought about between the device and the wall. The two airf lows
are preferably provided over the height of the whole opening.
This achieves that the entry of outside air and/or leakage of
usually conditioned inside air is reduced. An additional
advantage of providing an additional airflow is that disruptions
of the air curtain are prevented.
The angle between the wall and/or the air curtain on the
one hand and the additional airflow on the other during use
preferably lies in the range of 600-1200, more preferably
750-1050, and this angle most preferably amounts to about 900.
The additional airflow is preferably oriented here toward the
wall. It has been found that an additional airflow with a
component substantially perpendicularly of the direction of the
wall realizes a good screening and reduces leakage losses. This
means that particularly an angle of 750-1050 has been found
extremely suitable. The perpendicular component of the
additional airflow is preferably so large that the angle between
the additional airflow and the wall amounts to about 900. The
least disruption of the air curtain occurs here, and the
occurrence of leakage losses is simultaneously reduced.
In an advantageous preferred embodiment according to the
present invention the air curtain device comprises heating means
for heating at least a part of the air.
A part or even all of the blown-out air for the purpose of
the air curtain, and optionally also the additional airf low, can
be heated by providing heating means in the air curtain device.
This increases the comfort for persons passing through the air
curtain. In addition, the comfort of the interior space is
increased by reducing losses.
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The heating means preferably heat the air over at least part
of the height of the opening in which the air curtain is provided
during use. The energy required for the heating can remain
limited by heating only a part of the air curtain, and thereby
only a part of the total amount of air for the air curtain. The
first part of the height preferably amounts to about 2 to 2.5
metres. By providing warm air over a first part of the height
the greatest possible comfort is realized for persons passing
through the air curtain. The first part of the height is
preferably located up to a height of 2-2.5 metres from the ground.
It is however also possible not to heat a part of the air close
to the ground, since this makes only a limited contribution
toward the sense of comfort. It is thus possible for instance
to heat only a height corresponding to the height of the torso
and head of persons passing through the air curtain-
It is a further possibility to provide a plurality of heated
parts in vertical direction of the air curtain so that for
instance cold and heated air curtain parts are alternately
provided. Relatively cold air is preferably provided at the top
of the air curtain in order to thereby limit the loss of warm
air. This is preferably a height above 2 to 2.5 metres since this
does not detract, or only minimally, from the comfort.
In an advantageous preferred embodiment according to the
present invention the air curtain device comprises a speed
control for adjusting a flow speed over the height of the air
curtain and/or of the first and second outflow opening.
Providing a speed control achieves that the speed of an
airf low in the air curtain, and if desired also in the additional
airflow, can be adjusted, for instance subject to the dimensions
of the opening and/or the distance between the device,
particularly the outflow openings, and the wall. In addition to
adjusting a single air speed over the whole height of the air
curtain, it is also possible according to the invention to apply
a variation in speed over the height of an air curtain. The
comfort can hereby be further enhanced. In addition, the
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efficiency of the device is hereby increased. Using the speed
control a lower speed of the air can for instance be set at a
height corresponding to the head height of persons passing
through the air curtain. The comfort of these persons is hereby
5 enhanced. By varying the speed of the airflow over the height
of the air curtain it is further possible to influence the play
of forces such that energy losses are further limited. In
addition or alternatively, the amount of air can be distributed
over the substantially horizontal air curtain and the additional
airflow using the speed control. This distribution preferably
depends on specific conditions, such as for instance the
prevailing wind direction.
In a further advantageous preferred embodiment according
to the present invention an outflow opening is provided on either
side of the air curtain.
Providing an outflow opening or series of outflow openings
on both sides of the air curtain, in practice therefore on both
sides of the opening at which the air curtain is provided during
use, achieves that a good air curtain is realized over the whole
width of the opening.
In a further advantageous preferred embodiment according
to the present invention the air curtain device comprises
adjusting means for blowing out air differently from the outflow
openings on either side of the air curtain during use.
The length of the airflow from the two outflow openings or
series of outflow openings can be adjusted by providing the
adjusting means. This achieves that the location where these two
airflows come into mutual contact can be realized at a desired
position. This means for instance that the airf lows do not come
into contact with each other in the centre, but more to a side
of the opening. This further increases comfort. In addition, the
prevailing wind direction can hereby be taken into account such
that the disruptive influence thereof is minimized.
In a further advantageous preferred embodiment according
to the present invention the air curtain device comprises control
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means for controlling adjusting means and/or speed control on
the basis of ambient conditions.
Controlling the adjusting means and/or speed control on the
basis of ambient conditions achieves that the air curtain can
be adapted to the prevailing conditions in the immediate vicinity
thereof. In the case an air curtain is provided at an opening
to the outside, the ambient conditions are for instance
temperature differences, wind speeds and/or wind directions.
This avoids inter alia the air curtain having to be
over-dimensioned. The use of energy is hereby brought into line
with the actual need. The comfort is also increased here. A more
efficient air curtain is hereby obtained.
The invention further also relates to a method for realizing
an air curtain with an air curtain device as described above.
Such a method provides the same effects and advantages as
those stated in respect of the air curtain device.
Further advantages, features and details of the invention
are elucidated on the basis of preferred embodiments thereof,
wherein reference is made to the accompanying drawings, in which:
- figure 1 shows a view of an air curtain device according
to the invention;
- f igure 2 shows an alternative embodiment of the air curtain
device according to the invention;
- figure 3 shows a further alternative embodiment of the air
curtain device according to the invention;
- figure 4 shows a top view of an air curtain device as
according to figure 2; and
- figure 5 shows a view of a velocity profile obtained in an
opening without an air curtain.
An air curtain device 2 (figure 1) is provided in the
vicinity of an opening 4 in a wall 6. Device 2 comprises a first
upright 8 provided with a lower part 10 and an upper part 12.
A second upright 14 is placed on the other side of opening 4 close
to opening 4, wherein upright 14 consists of a lower part 16 and
an upper part 18. Lower parts 10, 16 and upper parts 12, 18 are
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provided at a small angle to each other, for instance in order
to prevent torsion of air curtain 22. Uprights 8, 14 are provided
with a series of outflow openings 20 with which air is blown out
in order to realize an air curtain 22 in opening 4. In a direction
toward wall 6 uprights 8, 14 are provided with second outflow
openings 23 to enable a secondary airflow 24 to be realized for
the purpose of preventing leakage losses.
An alternative air curtain device 26 (figure 2) consists
of a first upright 28 and a second upright 30 placed on either
side of an opening 4 in a wall 6. Air curtain 32 is realized by
allowing air to flow out of outflow openings 20 at uprights 28,
30. Secondary airflows 34 directed toward wall 6 are realized
from uprights 28, 30 with second airflow openings 33.
A further alternative air curtain device 36 (figure 3)
consists of a upright 28 provided on a side of opening 4. Upright
28 is provided with a series of outflow openings 20 for realizing
an air curtain. Upright 28 is further connected to a beam 38 in
which are provided second outflow openings 40 from which air can
be blown in order to realize secondary airflow 42. In this
embodiment secondary airflow 42 is directed substantially
vertically and therefore also makes a large angle with the air
curtain close to opening 4. A screening can be realized without
loss of installation space by positioning the beam 38 outside
the immediate opening 4.
An air curtain 32 (figure 4), as can for instance be realized
in use with the alternative embodiment of air curtain device 26,
is provided with two uprights 28, 30 on either side of an opening
4. The larger part of the air is used to realize air curtain 32.
A smaller part of the air is used to realize the additional or
secondary airflow 34. In the shown embodiment airflow 34 is
provided at an angle of 90 relative to air curtain 32, and is
directed toward wall 6.
The air can optionally be heated wholly or partially by
providing air curtain device 2, 26, 36 with a heating spiral (not
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shown) . This particularly relates to the air of air curtain 22,
32.
A velocity profile 44 occurring in practice (figure 5) in
an opening without an air curtain runs from ground surface 46
to upper edge 48 of an opening 4_ Air from outside (on the left
in figure 5) is thus carried inside (on the right in figure 5)
for instance over a first height A, whereby the indoor climate
is disrupted. Conversely, air will move from inside to outside
in opposite direction over a height B of speed profile 44, whereby
wholly or partially conditioned air of an indoor climate is
carried outside, wherein energy is lost. The transition point
of the flow direction depends for instance on the conditions
prevailing inside and outside. Through the use of a speed control
in an air curtain device it is therefore possible to keep the
flow around the transition point to a minimum, since losses will
here be minimal. In addition, it is efficient in the case of the
shown opening to blow relatively cold air at the top of the air
curtain without this detracting from the comfort. In addition,
profile 44 shows that some torsion of air curtain 22, 32 may
occur. This can be prevented by providing an air curtain device
2 as shown in figure 1, wherein uprights 8, 14 comprise in the
height a plurality of parts which blow out air at an angle to
each other.
In order to obtain air curtain 22, 32 an air curtain device
2, 26, 36 is provided, wherein during use air is blown out of
first outflow openings 20 by activating the air displacing means,
usually in the form of a number of fans. This results in an air
curtain 22, 32. Air is likewise blown out of second outflow
openings 40 during use in order to realize an additional airflow
24, 34, 42. Leakage losses are hereby reduced.
In the shown embodiments uprights 8, 14, 28, 30 are provided
on either side of opening 4. It is also possible to suf f ice with
a single upright 8, 28, depending for instance on the dimensions
of opening 4. It is also possible to provide a number of uprights
on the other side of opening 4. It is thus possible to provide
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four uprights on either side of the opening, and on both sides
thereof, i.e. inside and outside. A part of the air displaced
with air displacing means or fans can be used to realize an
additional airflow 24, 34, 42. Alternatively, it is possible to
provide separate air displacing means, for instance in the form
of one or more fans, in order to obtain the additional airflow
24, 34, 42.
If desired, the air speeds can be controlled using a speed
control. A velocity profile can hereby be obtained along the
height of air curtain 22, 32. It is optionally possible also to
control the air speed of the additional airflow 24, 32, 42. The
speed control here for instance controls the rotation speed of
a fan. It is also possible for instance to vary the air
distribution over the outflow openings, or the outflow openings
themselves- By measuring ambient conditions, preferably the wind
direction and the wind speed, the amount of air required for air
curtain 22, 32 can be adjusted thereto using control means. These
control means for instance set the speed control and/or control
adjusting means. In an embodiment in which a plurality of
uprights 8, 14, 28, 30 are for instance provided, air can be
distributed over the different uprights. The position where the
airflows from either side of the opening come into contact with
each other can hereby be adjusted for instance such that the wind
direction has no or a minimal influence on air curtain 22, 32,
42.
The present invention is by no means limited to the above
described preferred embodiments thereof. The rights sought are
defined by the following claims, within the scope of which many
modifications can be envisaged. Air curtain device 2, 26, 36 can
thus be applied at many locations. Examples hereof are for
instance entrances to shops, loading and/or unloading positions
at warehouses or logistical centres, and climate-controlled
spaces.
