Note: Descriptions are shown in the official language in which they were submitted.
CA 2967088 2017-05-10
AIR CURTAIN APPARATUS
FIELD OF THE APPLICATION
[0M] The present application relates to air curtain
apparatuses of the type used to create an air curtain transverse to
a door to limit air infiltration through the door.
BACKGROUND OF THE ART
[0002] Air curtains, also known as air doors, are conventionally
used in industrial or commercial installations in which relatively
large doors must be occasionally opened and therefore result in heat
or energy losses. An air curtain is a continuous wide stream of air
that forms a thermal barrier lessening heat loss through the open
enclosure. Air curtains may be used when doors are repeatedly open,
for example in a commercial building with high occupancy. Air
curtain apparatuses create an air curtain, i.e., a flow of air
across the opened door to limit energy loss to the exterior, whether
it be heating energy loss or air conditioning energy loss.
NOM Conventional air curtains use squirrel cage ventilators.
However, such squirrel cage ventilators are relatively voluminous
and heavy, difficultly scalable, whereby there is room for
improvement.
SUMMARY OF THE APPLICATION
mom It is therefore an aim of the present invention to
provide a novel air curtain apparatus, addressing issues
related to the prior art.
[0005] Therefore, in accordance with an embodiment of the
present application, there is provided an air curtain
apparatus comprising: a generally upstanding duct having an
upper inlet and a lower inlet; a plurality of axial fan units
connected side-by-side to a wall of the duct, the axial fan
units having rotational axes parallel to one another to blow
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air from an interior of the duct in a flow direction generally
parallel to rotational axes; and means to selectively close
one of the inlets while opening the other of the inlets.
[0006] In accordance with another embodiment of the present
disclosure, there is provided an air curtain apparatus
comprising: a generally horizontal duct having at least one
inlet and defining at least one outlet in a wall thereof; a
plurality of axial fan units mounted side-by-side across the
at least one outlet defined in the wall of the duct, the axial
fan units having rotational axes generally parallel to one
another and side-by-side to blow air from an interior of the
duct to an exterior of the duct; and at least one grill
positioned adjacent to the axial fan units in a downstream
flow path of the axial fan units, the at least one grill
directing an air flow of the axial fan units into a downwardly
directed air curtain.
[0007] In accordance with yet another embodiment, there is
provided a method for creating an air curtain comprising:
collecting air in a duct; exposing the air in the duct to
side-by-side axial fan units blowing the air out of the duct
in a downward direction; exposing the air blown downstream by
the side-by-side axial fan units to at least one grill
directing the air into forming an air curtain directed
downwardly.
BRIEF DESCRIPTION OF THE DRAWINGS
WM Fig. 1 is a perspective view, partly fragmented, of an
air curtain apparatus in accordance with the present disclosure;
[0009] Fig. 2 is an enlarged fragmented perspective view of an
axial fan unit of the air curtain apparatus of Fig. 1;
[00] Fig, 3A is a schematic view showing a use of the air
curtain apparatus of Fig. 1 in a vertical arrangement relative to a
door with ceiling air in the operation;
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Fig. 3B is a schematic view of the air curtain apparatus
of Fig. 3A in a floor inlet operation;
[0012] Fig. 4 is a schematic view of the air curtain apparatus
of Fig. 1 in a horizontal arrangement;
[0013] Fig. 5 is a perspective view of an air curtain apparatus
used as a booster in a ventilation system; and
[0014] Fig. 6 is a schematic view the air curtain apparatus of
Fig. 1 in a horizontal arrangement, with its air make-up unit.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
gmlq Referring to the drawings and, more particularly, to
Figs. 1 and 2, there is shown an air curtain apparatus in accordance
with the present disclosure at 10. The air curtain apparatus 10 is
of the type that is used to create an air curtain in numerous
different applications, especially in industrial and/or commercial
settings, across closable openings, such as entrance/exit sliding
doors (Figs. 3A and 3B) and garage doors at reception docks or
garages (Figs. 1 and 4). Other uses are contemplated as well. For
clarity and consistency, the expression air curtain is used herein
although such apparatuses may also be known as air door, etc. The
apparatus described herein is one that produces a continuous wide
stream of air that forms a thermal barrier lessening heat loss
through an open door or open enclosure.
umq Referring to Figs. 1 and 2, the air curtain apparatus 10
is shown having axial fan units 20 supported by an integrated duct
30. The air curtain apparatus 10 may also comprise a supporting
structure 40 (Fig. 4), a trigger switch 50 (Figs. 3A and 3B),
heating coils 60 and a thermostat 70.
[0017] Referring to Fig. 1, the air curtain apparatus 10 is
constituted of multiple side-by-side axial fan units 20, mounted to
the integrated duct 30, to form a self-supported upstanding
structure. The axial fan units 20 are arranged to be side-by-side
and thus form a stack (Fig. 1) or row of axial fans depending on the
orientation of the air curtain apparatus 10, the air curtain
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apparatus 10 being in a vertical orientation in Fig. 1. The air
curtain apparatus 10 is said to be modular in that axial fan units
20 may readily be attached or detached from the air curtain
apparatus 10 during manufacturing, to create air curtain apparatuses
of different heights (in the vertical orientation) or different
length (for horizontal use). Moreover, in an embodiment, the axial
fan units 20 are electrically wired so as to be independently
powered (e.g., off the 120V general supply), such that failure of
one of the axial fan units 20 does not cause a complete shutdown of
the air curtain apparatus 10. Hence, the air curtain apparatus 10
has a redundancy for continuous operation. The expression side-by-
side may describe the fact that the axial fan units 20 are in a
parallel arrangement relative to one another, as opposed to being
serially arranged in a duct.
[0018]
Each of the axial fan units 20 is of the type having a
square or rectangular housing 21 for a circular outlet 22. A fan 23
blows air through the outlet 22. The axial fan unit 20 is said to
be axial in that an axis of rotation of the fan 23 is generally
parallel to a flow direction out of the fan unit 20. The axis of
rotation of the axial fan unit 20 is generally shown at X in Fig. 2,
and this orientation is advantageous in that the side-by-side
arrangement of axial fan units 20 is relatively compact compared to
squirrel cages. The
axial fan units 20 may be direct drive or
pulley-driven units. In the shown embodiments, the axial fan unit 20
have their respective fan axes generally parallel to one another
(i.e., parallel, quasi-parallel, within 10 degrees of bring
parallel).
[0019]
Referring to Figs. 1 and 2, grills 24 cover the various
outlets 22. As show in Fig. 2, a single grill 24 may be sized to
cover multiple outlets 22, but it is considered to provide one grill
24 per outlet 22.
According to an embodiment, the grill 24 is
double louvered (also known as double louver grill or grille), with
fixed vertical and horizontal louvers, to form a grid of square
vents. The double louvered grill is arranged so as to direct the
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air flow in a direction substantially parallel to the rotational
axis of the fans 23. Other arrangements are considered, such as a
louvered grill, circular grill, .etc. The air curtain apparatus 10
must create a flow that is parallel to a plane of an opening, and
the axial fan units 20 are configured with the grills 24 and
oriented to give the air flow this parallel direction. Accordingly,
the air curtain is created by the concurrent action of the multiple
axial fan units 20 all blowing air in the same direction. As an
alternative embodiment, the axial fan units 20 may be inside to
build pressure in the integrated duct 30, with the air exiting
through the grills 24 in a generally laminar stream as guided by the
grills 24. In an embodiment, the double louvered grill 24 defines
square or rectangular vents having dimensions ranging from 0.375" to
1.125" (e.g., 0.5" x 0.5") in length and width, with a depth of at
least 0.25", to create the directional air flow.
[NM
Referring to Fig. 2, connection bars 25 may be used to
align the axial fan units 20 in the side-by-side relationship shown.
Other connection arrangements are contemplated, for instance using
the structural integrity of the housings 21 or of the integrated
duct 30, among other possibilities.
[0021] The
integrated duct 30 is typically made of sheet metal
that forms a passage for air. The fan units 20 are directly mounted
to an opening in a wall of the integrated duct 30, with necessary
sealing to limit or avoid air leaks. Accordingly, the axial fan
units 20 direct air from an interior of the integrated duct to an
exterior thereof. The
integrated duct 30, when the air curtain
apparatus 10 is used in a vertical configuration as in Figs. 1, 2
and 3A/3B, may have a lower or floor inlet 31 having its own louver
31A and an upper or ceiling inlet 32 with its own louver 32A
(Figs. 3A and 3B). Although the expressions "floor" and "ceiling"
are used, it is pointed out that the inlet 31 may be spaced from the
floor and not directly on the floor and the ceiling inlet 32 may be
spaced from the ceiling, not directly at the ceiling. In other
words, the floor inlet 31 is at an end of the integrated duct 30
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that is adjacent to the floor, whereas the ceiling inlet 32 is at an
end of the integrated duct 30 that is adjacent to the ceiling.
Moreover, although louvers are described, alternative components may
be used, such as traps, doors, flaps, covers. For instance, it is
considered to manually select and close/open the inlets with
appropriate components.
[0022] The louvers 31A and 32A are selectively actuated based on
the conditions of operation. For instance, it is known that hot air
has a lower density than cold air. In the winter months, the air
curtain apparatus 10 may close the lower louver 31A and open the
upper louver 32A to force warmer air into the integrated duct 30 as
shown in Fig. 3A. In such winter use, hot air may be blown across
the door to limit infiltration of cold air. Likewise, in summer
months in which a dwelling is air-conditioned, the lower louver 31A
may be opened while the upper louver 32A may be closed to force cold
air across the opening of a door and thus prevent hot air
infiltration or cold air escape.
[0OD] The operation of the louvers 31A and 32A may be commanded
by the thermostat 70 that measures the outdoor temperature and
therefore controls the louvers 31A and 32A as a function of the
exterior temperature. Considering that the doors are often closed,
the trigger switch 50 may determine when the air curtain apparatus
is to be used. The trigger switch 50 may be a position switch
that automatically opens the air curtain apparatus 10 when the door
is opened, a limit switch that is triggered by movement of a door,
or an optical switch that views the door opening.
pozq Additional heat or cold may be provided by heating coils
60 located in the air curtain apparatus 10. For example, the heating
coils may be electric coils, or may also refrigerant or coolant
coils, or gas burner coil, in which a fluid circulates for heat
exchange with the air. It is also considered to have coils of
refrigerant from a refrigeration system passing the air curtain
apparatus 10 to condition the air before forming the air curtain.
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[0025]
According to an embodiment, the various axial fan units
20 of the air curtain apparatus 10 are independently connected to
the power system, such that failure of one of the axial fan units 20
will not result in a complete outage of the air curtain apparatus
10. The axial fan units 20 may be controlled in speed by a common
rheostat adjusting a powering of the axial fan units 20. In
an
embodiment, the axial fan units 20 may be calibrated to operate
within a given decibel level.
[0026]
Referring to Fig. 4, an alternative embodiment is shown,
in which the air curtain apparatus 10 is oriented horizontally. In
such a case, there may be no need for an integrated duct 30, as the
integrated duct 30 is particularly useful to get inlet air at
different locations, i.e., the ground or the ceiling. It is however
considered to provide the air curtain apparatus 10 with a duct.
Such a duct may bend to have a floor inlet for summer use, for
example. The supporting structure 40 is used to overhang the axial
fan portion of the apparatus 10 above the opening. For example, the
supporting structure 40 comprises chains supporting the axial fan
units 20 at a given distance from the ceiling (e.g., at least 12").
The arrangement of Fig. 4 is particularly well suited to operate in
winter, as the air curtain apparatus 10 supplies itself with warmer
air mass that accumulates at the ceiling. Hence, the air curtain
apparatus 10 may have access to sufficiently warm air to operate in
winter conditions without having to further heat the air. It
is
also contemplated to provide a heating coil(s) 60 in a duct of the
air curtain apparatus 10 as mounted horizontally as in Fig. 4.
[0027]
Referring to Fig. 5, in accordance with another
embodiment, a plurality of the axial fan units 20 in the side-
by-side arrangement are mounted to a ventilation duct 80 of
the main ventilation system. An
adaptor 81 may be used
depending on the shape of the ventilation duct 80. In such an
arrangement, the axial fan units 20 act as a booster on the
ventilation system to create the air curtain. It
may be
necessary to add other components to the ventilation system
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considering the suction that will be caused by the boosting,
such as air intakes, louvers, automatic on/off switches, etc.
In the embodiment of Fig. 5, the axial fans may be in the duct
80, with the double louvered grills 24 being surface mounted
or being connected to the adaptor 81.
[0028]
Referring to Fig. 6, in accordance with yet another
embodiment, the air curtain apparatuses 10 share a common
dedicated ventilation system including a rooftop air make-up
unit 90. The air make-up unit 90 feeds off outside air, and
may have an integrated fan 91, to supply the integrated duct
30 with air pressure. The
integrated fan 91 may be any
appropriate type of fan, such as a squirrel cage fan, or one
or more of the axial fan units 20. The air make-up unit 90
may have a heating coil(s) 60. The air curtain apparatuses 10
then create the appropriate flow and curtain effect.
[0029] The
air curtain apparatus 10 described herein may
have different characteristics in comparison to other air
curtain systems, such as those including squirrel cage fans.
For example, the air curtain apparatus 10 of the present
disclosure is more compact, lighter, and may be less
expensive, with an effective flow rate to energy consumption
rapport. The
axial fan units 20 are capable of being
subjected to relatively high levels of static pressure,
enabling their use in the arrangement of Fig. 5, for example,
in ventilation ducts 80, in a retrofit manner for example.
[0030]
Therefore, the air curtain apparatus 10 operates a
method for creating an air curtain, by collecting air in a
duct; exposing the air in the duct to side-by-side axial fan
units blowing the air out of the duct in a downward direction;
exposing the air blown downstream by the side-by-side axial
fan units to at least one grill directing the air into forming
an air curtain directed downwardly.
Collecting air in the
duct includes inletting air from an air mass gathered proximal
to and below a ceiling. Collecting air in the duct includes
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inletting air proximally to a floor. Inletting air proximally
to the floor and inletting air from the air mass gathered
proximal to and below the ceiling are selected as a function
of a temperature.
Collecting air in the duct includes
collecting air from an existing ventilation system.
Collecting air in the duct includes collecting air from a
rooftop make-up air unit.
Exposing the air in the duct to
side-by-side axial fan units is performed when a door opening
is detected.
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