AIR CURTAIN APPARATUS

Abstract

An air curtain apparatus comprises 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 are 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. One or more grills are positioned adjacent to the axial fan units in a downstream flow path of the axial fan units, the grill(s) directing an air flow of the axial fan units into a downwardly directed air curtain. A method for creating an air curtain is also provided.

Description

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority on U.S. Provisional Patent Application No. 62/504,161, filed on May 10, 2017.

FIELD OF THE APPLICATION

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

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.

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

It is therefore an aim of the present invention to provide a novel air curtain apparatus, addressing issues related to the prior art.

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 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.

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.

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

FIG. 1 is a perspective view, partly fragmented, of an air curtain apparatus in accordance with the present disclosure;

FIG. 2 is an enlarged fragmented perspective view of an axial fan unit of the air curtain apparatus of FIG. 1;

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;

FIG. 3B is a schematic view of the air curtain apparatus of FIG. 3A in a floor inlet operation;

FIG. 4 is a schematic view of the air curtain apparatus of FIG. 1 in a horizontal arrangement;

FIG. 5 is a perspective view of an air curtain apparatus used as a booster in a ventilation system; and

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

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.

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.

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 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 10 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.

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).

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 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″×0.5″) in length and width, with a depth of at least 0.25″, to create the directional air flow.

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.

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 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.

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.

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 10 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.

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.

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.

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.

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 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.

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 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.

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.

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 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.

Claims

1. 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.

2. The air curtain apparatus according to claim 1, wherein the at least one inlet is open to a space proximal to the ceiling.

3. The air curtain apparatus according to claim 2, comprising two of said inlet, with one said inlet being open to a space proximal to the floor.

4. The air curtain apparatus according to claim 3, further comprising automated louvers at each said inlet to selective open and close access to the inlets.

5. The air curtain apparatus according to claim 4, further comprising at least one thermostat operatively connected to the automated louvers to control their operation.

6. The air curtain apparatus according to claim 1, wherein the at least one inlet is connected to an existing ventilation system.

7. The air curtain apparatus according to claim 1, wherein the at least one inlet is connected to a dedicated rooftop make-up air unit.

8. The air curtain apparatus according to claim 7, wherein the rooftop make-up air unit has a heating coil.

9. The air curtain apparatus according to claim 7, wherein the rooftop make-up air unit has at least one fan.

10. The air curtain apparatus according to claim 9, wherein the fan of the rooftop make-up air unit is a squirrel cage fan.

11. The air curtain apparatus according to claim 1, wherein the at least one grill is at least one double louver grill.

12. The air curtain apparatus according to claim 11, wherein a plurality of vents defined by the double louver grill each have a rectangular shape having a length ranging between 0.375″ and 1.125″.

13. The air curtain apparatus according to claim 12, wherein the plurality of vents defined by the double louver grill each have a width ranging between 0.375″ and 1.125″.

14. The air curtain apparatus according to claim 12, wherein the plurality of vents defined by the double louver grill each have a depth of at least 0.25″.

15. The air curtain apparatus according to claim 1, comprising one of the at least one grill for each said axial fan unit.

16. The air curtain apparatus according to claim 1, wherein each of the plurality of axial fan units is connected independently to a powering system.

17. The air curtain apparatus according to claim 1, further comprising a door sensor determining an opening of at least one door associated with the air curtain apparatus, the door sensor operatively connected to the axial fan units to control their operation as a function of the opening of the at least one door.

18. The air curtain apparatus according to claim 1, comprising at least one heating coil in the duct.

19.-26. (canceled)