Apparatus for tensioning pliable airducts while supporting internal HVAC components

Abstract

To provide an apparatus for tensioning pliable airducts while supporting internal HVAC components.SOLUTION: An airduct system includes an airduct having an elongate tubular wall of a pliable material. The airduct system further includes a frame disposable inside the tubular wall of the airduct, the frame including a hoop to support the tubular wall in a radial direction, the hoop to define an opening to provide passage of a flow of air along a length of the airduct. The airduct system also includes an HVAC component disposable within the tubular wall of the airduct, the HVAC component to be attached to and supported by the frame inside the airduct, the HVAC component to adjust a characteristic of the air.SELECTED DRAWING: Figure 1

Description

[Background technology]

[0001] [Related Applications]

[0002]

[0001]

[0003] This patent arises out of a nonprovisional patent application which claims the benefit of U.S. Provisional Patent Application No. 63 / 024,061, filed May 13, 2020. U.S. Provisional Patent Application No. 63 / 024,061 is incorporated herein by reference in its entirety. Priority to U.S. Provisional Patent Application No. 63 / 024,061 is hereby claimed.

[0004] [Field of Disclosure]

[0005] This patent relates generally to flexible wall air ducts, and more specifically to an apparatus for tensioning a flexible air duct while supporting interior HVAC (heating, ventilation, and air conditioning) components.

[0006] [background]

[0007]

[0003] Ductwork is often used to transport conditioned air (e.g., heated, cooled, filtered, etc.) emitted by fans and distribute the air to rooms or other areas within a building. Ducts are typically formed from rigid metals such as steel, aluminum, or stainless steel. In many facilities, the ducts are hidden above a suspended ceiling for convenience and aesthetics. However, in warehouses, manufacturing plants, and many other buildings, the ducts are suspended from the roof of the building and are therefore exposed. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a side view of an exemplary air duct system constructed in accordance with the teachings disclosed herein, showing a blower of the example air duct system that is not energized. [Diagram 2]FIG. 2 is a side view similar to FIG. 1, but showing the embodiment air duct system when the blower is energized. [Diagram 3] FIG. 3 is a cross-sectional view taken along line 3-3 of FIG. [Figure 4] FIG. 4 is a top view of an example air duct system constructed in accordance with the teachings disclosed herein, the air duct system including an elbow. [Diagram 5] FIG. 5 is a top view of an example air duct system constructed in accordance with the teachings disclosed herein, the air duct system including a T-section. [Figure 6] FIG. 6 is a top view of an example air duct system constructed in accordance with the teachings disclosed herein, the air duct system including an intersection area. [Figure 7] FIG. 7 is a side view similar to FIG. 2 showing another example air duct system constructed in accordance with the teachings disclosed herein, the air duct system including an example air straightener. [Figure 8] FIG. 8 is a perspective view of the example frame and example air straightener shown in FIG. [Figure 9] FIG. 9 is a top view similar to FIG. 4, but with an air duct system including an example flow turning device constructed in accordance with the teachings disclosed herein. [Figure 10] FIG. 10 is a cross-sectional view taken along line 10-10 of FIG. [Figure 11] FIG. 11 is a cross-sectional view similar to FIG. 3, but showing an air duct system having an embodiment frame-mounted sensor that provides an electrical feedback signal. [Figure 12] FIG. 12 is a cross-sectional view similar to FIG. 3, but showing an air duct system having an example frame mounted sensor providing an air feedback signal. [Figure 13] FIG. 13 is a cross-sectional view similar to FIG. 3, but showing an embodiment of a tubular shaft carrying fluid. [Figure 14]FIG. 14 is a cross-sectional view similar to FIG. 3, but showing an air duct system having an embodiment frame-mounted tube for conveying fluid. [Figure 15] FIG. 15 is a cross-sectional view similar to FIG. 3, but showing an air duct system with an embodiment nozzle for humidification. [Figure 16] FIG. 16 is a cross-sectional view similar to FIG. 3, but showing an air duct system having an embodiment of a frame-mounted electrical resistance wire. [Figure 17] FIG. 17 is a cross-sectional view similar to FIG. 3, but showing a tubular shaft containing an example electrically resistive wire. [Figure 18] FIG. 18 is a cross-sectional view similar to FIG. 3, but showing an air duct system having an embodiment of a frame mounted heat exchanger. [Figure 19] FIG. 19 is a cutaway side view of FIG. [Figure 20] FIG. 20 is a cross-sectional view similar to FIG. 3, but showing an air duct system having an example baffle constructed in accordance with the teachings disclosed herein. [Figure 21] FIG. 21 is a cross-sectional view similar to FIG. 3, but showing an air duct system having another embodiment of a baffle constructed in accordance with the teachings disclosed herein. [Figure 22] FIG. 22 is a cross-sectional view similar to FIG. 3, but showing an air duct system having an example baffle and valve constructed in accordance with the teachings disclosed herein, with the valve shown closed. [Diagram 23] FIG. 23 is a cross-sectional view similar to FIG. 22, but showing the valve partially open. [Figure 24] FIG. 24 is a cross-sectional view similar to FIGS. 22 and 23, but showing the valve open. [Diagram 25] FIG. 25 is a cutaway top view of FIG. [Figure 26] FIG. 26 is a cutaway top view of FIG. [Figure 27] FIG. 27 is a cutaway top view of FIG. [Figure 28]FIG. 28 is a cutaway top view similar to FIG. 26, but showing a valve connected to an embodiment valve control device. [Figure 29] FIG. 29 is a cross-sectional view similar to FIG. 3, but showing an air duct system having a valve of another embodiment constructed in accordance with the teachings disclosed herein, with the valve shown closed. [Diagram 30] FIG. 30 is a cross-sectional view similar to FIG. 29, but with the valve partially open. [Diagram 31] FIG. 31 is a cross-sectional view similar to FIGS. 29 and 30 but showing the valve in an open position. [Diagram 32] FIG. 32 is a cross-sectional view similar to FIG. 3, but showing an air duct system having a valve of another embodiment constructed in accordance with the teachings disclosed herein, with the valve shown closed. [Diagram 33] FIG. 33 is a cross-sectional view similar to FIG. 32, but with the valve partially open. [Diagram 34] FIG. 34 is a cross-sectional view similar to FIGS. 32 and 33 but showing the valve in an open position. [Diagram 35] FIG. 35 is a cross-sectional view similar to FIG. 3, but showing an air duct system having a valve of another embodiment constructed in accordance with the teachings disclosed herein, with the valve shown closed. [Diagram 36] FIG. 36 is a cross-sectional view similar to FIG. 35, but showing the valve partially open. [Figure 37] FIG. 37 is a cross-sectional view similar to FIGS. 35 and 36, but showing the valve in an open position. [Figure 38] FIG. 38 is a top view similar to FIG. 9, but with an air duct system including another embodiment of a flow swirler constructed in accordance with the teachings disclosed herein. [Figure 39]FIG. 39 is a top view similar to FIGS. 9 and 38, but with an air duct system including another embodiment of a flow swirler constructed in accordance with the teachings disclosed herein.

[0043] Unless otherwise specified, descriptors such as "first," "second," "third," and the like are used herein without implying or otherwise indicating any sense of priority, physical order, placement in a list, and / or ordering, but are used only as labels and / or arbitrary names to distinguish elements to facilitate understanding of the disclosed embodiments. In some embodiments, the descriptor "first" may be used to refer to an element in the detailed description, while the same element may be referenced in the claims with a different descriptor such as "second" or "third." In such cases, it is to be understood that such descriptors are used only to clearly identify elements that may otherwise share the same name, for example. As used herein, "approximately," "substantially," and "about" refer to dimensions that may not be exact due to manufacturing tolerances and / or other real-world imperfections.

[0009] Detailed Description

[0010]

[0044] In warehouse and manufacturing environments, where preventing air contamination of inventory is important, metal ducts can pose problems.

[0011]

[0045] For example, temperature changes within a building or temperature differences between the duct and the air being conveyed can cause condensation to form both inside and outside the duct. The presence of condensed moisture inside the duct promotes the growth of mold or bacteria, which is then carried by the duct to rooms or other areas served by the conditioned air. For spaces ventilated by exposed ducts, condensation on the exterior of the duct can drip onto inventory or personnel below. Dripping can cause unsafe working conditions, damage / contamination of equipment, or products (especially in food processing facilities) below the duct, etc.

[0012]

[0046] Additionally, metal ducts with local discharge resistors can create unpleasant drafts and unbalanced local heating or cooling within the building. In many food processing facilities, where the target temperature is around 42 degrees Fahrenheit, cold air drafts can be particularly unpleasant and potentially unhealthy.

[0013]

[0047] Many of the above problems associated with metal ducts are overcome by the use of flexible fabric ducts. Such ducts typically have a pliable fabric wall (often porous) that expands to a roughly cylindrical shape due to the pressure of the air conveyed by the duct. Condensation does not tend to form on the outer walls of fabric ducts to the extent that it does on metal ducts in the same environment, due in part to fabric having a lower thermal conductivity than metal ducts. Furthermore, the inherent porosity of the fabric used and / or additional vents distributed along the length of the fabric duct allow for a relatively wide and uniform distribution of air into the or room being ventilated. The uniform distribution of airflow along the length of the duct effectively ventilates the walls of the fabric duct itself, as opposed to only local registers, thereby further inhibiting mold and bacterial growth.

[0014]

[0048] In the embodiments of the fabric air ducts disclosed herein, the flexible tubular walls of the embodiment air ducts are held in an expanded shape by a relatively rigid internal frame. In some embodiments, the air ducts can also support various internal HVAC components (also referred to herein as HVAC fixtures), such as guide vanes, fixed dampers, adjustable valves, valve controls, sensors, air filters, fans, and heat exchangers. More specifically, in some embodiments, such HVAC components are internally configured within the length of the flexible air duct (e.g., such that the tubular walls of the flexible air duct radially surround the components). In some embodiments, such HVAC components are held in place within the air duct by being attached to and / or supported by the internal frame. In some embodiments, the HVAC components arranged within the flexible air duct are spaced from both ends (e.g., upstream and downstream ends) of the air duct such that the tubular walls of the air duct are spaced away from the HVAC components in both directions. In some embodiments, the flexible air duct, corresponding to either the supply length of the air duct or the return length of the air duct, is formed with at least two separate air ducts corresponding to separate elongated tubes. In some such embodiments, the HVAC component is located at or between adjacent ends (e.g., intermediate ends) of the two separate air duct sections. In some such embodiments, the HVAC component still resides radially inside the flexible air duct, with the separate ends of the two separate sections radially connected around the HVAC component. In other embodiments, the adjacent ends of the two separate air duct sections are separated at a distance by the HVAC component located between them. To heat or cool the air flowing through the air duct, the frame of some embodiments includes a hollow shaft that carries a hot or cold fluid or carries an electrical resistance wire.In some embodiments, a variable air volume (VAV) control, which adjusts a valve to vary the airflow through the air duct, is mounted to the frame at a T-section or intersection section of the air duct.

[0015]

[0049] 1-39 show various example air duct systems including a relatively rigid interior frame that supports an air duct having tubular walls made of a flexible material. The frame also supports various interior HVAC components such as guide vanes, fixed dampers, adjustable valves, valve controls, sensors, air filters, fans, and temperature changing devices. 1-6 show some basic components of an example air duct system 10 (e.g., air duct system 10 af).

[0016]

[0050] In the embodiment shown in Figures 1-3, the air duct system 10 includes a frame 12, a flexible fabric air duct 14, at least one hanger 16, and a blower 18 (e.g., centrifugal fan, axial fan, etc.). To ventilate or otherwise condition a space 24 within a building, the blower 18 forces a flow of air (airflow) 20 through the air duct 14 in a generally longitudinal direction 22, which ultimately distributes the air to the target space 24. The term "longitudinal" as it relates to an air duct refers to the length or axial dimension of the duct. The longitudinal direction is the general path through which most air flows through the duct. For air ducts that are straight (e.g., the air ducts of the embodiments of Figures 1 and 2), the longitudinal direction is a straight line, even if the air actually flows through the entire length of the duct in a spiral or turbulent pattern. For air ducts that have one or more elbows or bends (e.g., the air duct embodiment of FIG. 4), the longitudinal directions are similarly curved. Air ducts that have one or more T-shaped sections (e.g., the air duct embodiment of FIG. 5), cross sections (e.g., the air duct embodiment of FIG. 6), or other types of manifolds to form multiple branch ducts, have multiple longitudinal directions (e.g., a longitudinal direction for each branch).

[0017]

[0051] The air duct 14 includes a tubular wall 26 formed of a pliable material. The term "pliable material" refers to a sheet of material that can be easily folded over itself, unfolded, and restored to its original shape without appreciable damage to the material. Cloth is an example of a pliable material, and sheet metal is an example of a non-pliable material. Examples of specific materials for the tubular wall 26 include vinyl, polyester sheet, and polyester cloth. Some example materials used for the air duct 14 can result in a tubular wall 26 that is perforated, porous, gas impermeable, or a combination thereof (e.g., some porous areas and some gas impermeable areas). Some example materials are impregnated or coated with a sealant such as acrylic or polyurethane. Some example materials are uncoated. Examples of materials include fire or heat resistant. To discharge air from within the air duct 14 into the building space served by the air duct, the tubular wall 26 and / or end cap 28 of the air duct 14 may include one or more exhaust openings, such as, for example, cut-out openings, plastic or metal exhaust registers or nozzles, and / or porosity in the tubular wall or end cap material itself.

[0018]

[0052] To provide radial support 30 (perpendicular to longitudinal direction 22) to tubular wall 26, frame 12 is relatively stiffer and less flexible than tubular wall 26. In some embodiments, frame 12 also holds tubular wall 26 taut in longitudinal direction 22. Example materials for frame 12 include metal, fiberglass, relatively rigid plastic, and combinations thereof.

[0019]

[0053] In the illustrated embodiment, the frame 12 includes a plurality of hoops 32 (e.g., a first hoop 32a and a second hoop 32b) and a shaft 34 extending between the hoops 32 to connect them to one another and maintain the position of each hoop 32 relative to the other hoops 32. The shaft 34 in the embodiment may be a rod, bar, tube, and / or pipe. In some embodiments, the shaft 34 is solid. In some embodiments, the shaft 34 is tubular. The hoops 32 are secured to the shaft 34 at longitudinally spaced locations within the air duct 14. In some embodiments, one or more spokes 36 extending between the hoops 32 and a hub 38 hold the shaft 34 in a radially centered position, as shown in Figures 1-3. In some embodiments, one or more shafts 34 are positioned against or adjacent the inner surface of the tubular wall 26 and extend in the longitudinal direction 22 directly connected to the hoops 32. In such an embodiment, the spokes 36 and hub 38 may be omitted.

[0020]

[0054] The hanger 16 in the embodiments of Figures 1-3 is illustrated diagrammatically to represent any means of supporting the air duct 14 by suspending it from a structural support 46. In some embodiments, the hanger 16 is a cable, rod, or strap that extends vertically between an anchor point 40 on the air duct 14 and an overhead rod, bar, beam, or cable 42. Examples of attachment locations for the anchor point 40 include the hoop 32, spokes 36, shaft 34, and / or tubular wall 26. In some embodiments, a bracket 44 connects the cable 42 to the structural support 46 (e.g., a ceiling, truss, or beam).

[0021]

[0055] In the exemplary embodiment of FIG. 4 (plan view), the embodiment air duct system 10a includes an elbow 48 that redirects the air flow 20 along a curved or angled turn. The elbow 48 portion of the air duct 14 includes a series of tubular sections 50 that are stitched or otherwise joined to form a desired air flow path shape. In some embodiments, the tubular sections 50 include the same pliable material as the other tubular wall portions of the air duct 14. As with the straight portions of the air duct 14, a hoop 32 is positioned along the longitudinal dimension of the elbow to support the tubular wall 26 of the air duct 14. In some embodiments, the curved or articulated variation of the shaft 34 (e.g., shaft section 34') follows the general curvature of the elbow 48 that connects the hoops 32 to one another and maintains the position of each hoop 32 relative to the other hoops 32.

[0022]

[0056] In the illustrated embodiment of FIG. 5 (top view), the example air duct system 10b includes a T-section 52 for splitting the air flow 20 from an air duct connected to a blower into two branched air ducts positioned at right angles therefrom. In other embodiments, the T-section 52 can redirect the air flow 20 at any other angle or can include more than one branched air duct 14. In some embodiments, the T-section 52 of the air duct 14 includes the same pliable material as the other tubular wall portions of the air duct 14. The hoop 32 is positioned along the longitudinal dimension of the air duct 14 and supports the air duct 14.

[0023]

[0057] 6 (top view), the example air duct system 10c includes an intersection section 54 (also known as a manifold) for splitting the airflow 20 from the blower into three paths. In some embodiments, the intersection section 54 of the air duct 14 comprises the same pliable material as the other tubular wall portions of the air duct 14. The hoop 32 is positioned along the longitudinal dimension of the air duct 14 and provides support to the air duct 14.

[0024]

[0058] In the embodiment illustrated in Figures 7 and 8, the example air duct system 10d includes an air straightener 56 (also referred to herein as a turbulence straightener). The air straightener 56 directs the airflow 20 into a generally straight path to reduce (e.g., minimize) turbulence and other undesirable flow patterns. The air straightener 56 has one or more airflow guide vanes 58, each having a generally planar guide surface 60 extending from an upstream leading edge 62 to a downstream trailing edge 64. The guide surfaces 60 are substantially parallel (e.g., within plus or minus 10 degrees) to the longitudinal direction 22 and direct the airflow 20 in a parallel direction.

[0025]

[0059] In some embodiments, the guide vanes 58 are less flexible than the flexible material of the tubular wall 26. The relatively stiff material ensures that the guide vanes 58 are stiff enough to straighten the airflow 20 rather than bending it. In some embodiments, the guide vanes 58 include sheet metal and / or rigid plastic. To support a relatively stiff structure within the flexible wall air duct, the air straightener 56 is attached to and supported by the frame 12. In the embodiment shown in FIGS. 7 and 8, the air straightener 56 extends between two hoops 32a and 32b of the frame 12. In other embodiments, the air straightener 56 can extend farther than the distance between two adjacent hoops 32.

[0026]

[0060] 9 and 10 show an example air duct system 10e with an example flow swirler 66 to direct the airflow 20 through the elbow 48. In this example, the flow swirler 66 includes one or more guide vanes 68 each having a curved guide surface 70 that is substantially parallel to the longitudinal direction 22 and extends from an upstream leading edge 72 to a downstream trailing edge 73. The guide surface 70 guides the airflow 20 along the curved longitudinal direction 22 that extends through the elbow 48. As shown in the illustrated embodiment of FIGS. 38 and 39, the flow swirler 66 can be incorporated into elbows 134, 136 that are more compact than the elbow 48. These example elbows 134, 136 provide a zero or near zero radius swirl (as measured at the wall 26 of the air adduct 14) compared to the much larger radius swirl of the example elbow of FIG. 9. Thus, the elbows 134 , 136 may change the longitudinal direction 22 of the air duct 14 over a shorter length of the air duct 14 and may be constructed with fewer tubular sections 50 .

[0027]

[0061] In some embodiments, the guide vanes 68 are less flexible than the flexible material of the tubular wall 26 of the elbow 48. The relatively stiff material ensures that the guide vanes 68 are stiff enough to guide the airflow 20 rather than bending into it. In some embodiments, the guide vanes 68 include sheet metal and / or hard plastic. To support a relatively stiff structure within a flexible wall air duct, the pivoting device 66 is attached to and supported by the frame 12. In this embodiment, the frame 12 includes a curved or articulated shaft section 34' that aligns with the curved portion of the longitudinal direction 22.

[0028]

[0062] FIG. 11 illustrates an example air duct system 10f including one or more sensors 74 mounted to the frame 12. The frame 12 provides a more secure support for the sensor 74 than other more flexible portions of the air duct system 10f. Example mounting locations for the sensor 74 include the hoop 32, spokes 36, and shaft 34. The sensor 74 is positioned in fluid communication with the air flow 20 within the air duct 14 and provides a signal 76 that changes in response to changing conditions in the air 20. Examples of such conditions that may change and be detected by the sensor 74 include static air pressure, stagnation air pressure, air flow rate, air temperature, relative or total humidity, the presence or concentration of smoke, the presence or concentration of toxic gases, the concentration of carbon dioxide, the concentration of oxygen, the presence or concentration of particulates (e.g., dust), the presence or concentration of contaminants (e.g., mold, bacteria, viruses, etc.), and the like.

[0029]

[0063] Sensor 74 is shown diagrammatically to represent any device that provides a signal in response to some changing condition of air 20. Examples of sensor 74 include static pressure sensors, stagnation pressure sensors, pitot tubes (pneumatic or electronic), anemometers, temperature sensors, humidity sensors, smoke detectors, fire detectors, toxic gas sensors, carbon dioxide sensors, oxygen sensors, particulate sensors, etc. Example forms of signal 76 include air pressure signals and electrical signals. In the example shown in FIG. 12, sensor 74 is a stagnation pressure sensor 74a and signal 76 is air pressure. Signal 76 can be used to monitor or control air 20.

[0030]

[0064] 13-19 are illustrated embodiments of air duct system 10 including temperature changing devices 78 (e.g., devices 78a-f) disposed in heat transfer relationship with air 20. In the illustrated embodiment, temperature changing devices 78 are mounted to frame 12, which provides a more secure support than other more flexible portions of air duct system 10. The term "mounted" in reference to a device mounted to a frame means that the device is secured to, coupled to, supported by, supported by, or incorporated within the frame. Examples of mounting locations for temperature changing devices 78 include hoop 32, spokes 36, and shaft 34.

[0031]

[0065] In the illustrated embodiment of Fig. 13, the shaft 34 is hollow and functions as a conduit 78a to carry a fluid 80 (e.g., water, 20, refrigerant, carbon dioxide, salt water, etc.) to heat or cool the air glycol. In the illustrated embodiment of Fig. 14, one or more separate conduits 78b extending in the longitudinal direction 22 are attached to the spokes 36, shaft 34, and / or hoop 32 to carry a fluid 80 to heat or cool the air 20.

[0032]

[0066] The embodiment illustrated in Figure 15 is similar to the embodiment of Figure 14, but with the addition of one or more spray nozzles 78c that emit water from within tubes 78b to produce a water spray or mist 82 that humidifies the air 20. Depending on the humidity of the air and the temperature difference between the water 82 and the air 20, the one or more spray nozzles 78c change the humidity and / or temperature of the stream of air 20d.

[0033]

[0067] In the illustrated embodiment of Figure 16, one or more electrically resistive wires 78d extending in the longitudinal direction 22 are attached to the spokes 36, shaft 34, and / or hoop 32 to heat the air 20. In the illustrated embodiment of Figure 17, the shaft 34 is hollow and serves as a conduit that contains one or more electrically resistive wires 78e. The wall material of the shaft 34 transfers heat radially from the wire(s) 78e to the air 20.

[0034]

[0068] In the embodiment illustrated in FIGS. 18 and 19, the air duct system 10 includes a heat exchanger 78f mounted to the frame 12. In some embodiments, the heat exchanger 78f includes one or more heat transfer tubes 84 that carry a fluid in heat transfer relationship with the air 20. In the illustrated embodiment, the heat transfer tubes 84 are arranged in a serpentine configuration. In other embodiments, the heat transfer tubes 84 are arranged in a coil. In other embodiments, the heat exchanger 78f includes a plurality of heat transfer tubes 84 arranged in parallel between an inlet manifold and an outlet manifold. In some embodiments, the heat exchanger 78f includes a plurality of fins 86 that facilitate heat transfer as the fluid 80 circulates through the heat transfer tubes 84. In the embodiment illustrated in FIGS. 18 and 19, the fluid 80 enters the heat transfer tubes 84 through an inlet tube 88 and exits through an outlet tube 90. In some embodiments, a bracket 92 rigidly couples the heat exchanger 78f to the hoop 32.

[0035]

[0069] As shown in Figures 20 and 21, in some embodiments, the air duct system 10 includes a baffle 94 (e.g., baffle 94a or 94b) attached to the frame 12. To withstand the pressure differential caused by the air flow 20 across the baffle 94, some embodiments of the baffle 94 are made of a relatively rigid material (e.g., sheet metal, hard plastic, etc.) that is less flexible than the tubular wall 26. Figure 20 shows the baffle 94a extending radially (e.g., radial direction 30 as shown in Figure 3) out from the shaft to provide a substantially fixed flow restriction with a circular intersection area perpendicular to the longitudinal direction. An airflow region 96 surrounds and extends radially from the periphery of the baffle 94a to the tubular wall 26. The baffle 94a and airflow region 96 are substantially centered within the air duct 14 with respect to the radial direction 30 (e.g., within 5 inches of the center). In some embodiments, the airflow area 96 is less than 80 percent of the cross-sectional area of ​​the air duct 14. In the embodiment shown in Figure 20, the airflow area 96 is the annular space between the outer periphery 98 of the baffle 94a and the inner surface 100 of the tubular wall 26.

[0036]

[0070] FIG. 21 shows a baffle 94b extending radially 30 inwardly from the tubular wall to provide a substantially fixed flow restriction. An airflow region 102 having a circular intersection area perpendicular to the longitudinal direction 22 extends inwardly from an inner periphery 104 of the baffle 94b and surrounded by the shaft 34. The baffle 94b and airflow region 102 are substantially centered within the air duct 14 with respect to the radial direction 30. In some embodiments, the airflow region 102 is less than 80 percent of the cross-sectional area of ​​the air duct 14. In the embodiment shown in FIG. 21, the airflow region 102 is a circular space defined by the inner periphery 104 of the baffle 94b. To reduce airflow turbulence that can result from a solid (relatively impermeable) baffle, some embodiments of the baffle 94 are permeable, include perforations, or are constructed of a permeable material (e.g., a perforated plate or woven screen), as shown in the illustrated embodiments of FIG. 20 and FIG. 22-FIG. 24.

[0037]

[0071] In the illustrated embodiment of Figures 22-27, a valve 106 is added to the air duct system 10 in an embodiment that provides an adjustable flow restriction. Figures 25, 26, and 27 are top views of Figures 22, 23, and 24, respectively. In the illustrated embodiment, the valve 106 is centered within the inner periphery 108 of the stationary baffle 110. In this embodiment, the valve 106 includes two flaps 112 made of a relatively rigid material (e.g., sheet metal or hard plastic) that is stiffer than the pliable material of the tubular wall 26. The flaps 112 are connected by a hinge 114 that allows the valve 106 to be selectively moved to a closed position (e.g., as shown in the embodiment of Figures 22 and 25), a partially open position (e.g., as shown in the embodiment of Figures 23 and 26), and a fully open position (e.g., as shown in the embodiment of Figures 24 and 27).

[0038]

[0072] Any suitable mechanical means may be used to maintain the valve 106 in a desired position. Alternatively, a controller 116 may be added to automatically adjust the position of the valve 106, as shown in the illustrated embodiment of FIG. 28. Such a controller may be known as a VAV, or variable air volume controller. To provide positive support for the valve 106 and / or controller 116, some embodiments of the valve 106 and / or controller 116 are mounted to the frame 12 and operably connected to the valve 106. In some embodiments, the controller 116 is mounted to the frame 12 at the T-section 52 (e.g., as shown in the embodiment of FIG. 5) or at the intersection section 54 (e.g., as shown in the embodiment of FIG. 6) to control the airflow 20 to the supply and / or branch air ducts. In some embodiments, the controller 116 is communicatively coupled (e.g., wirelessly and / or via wires) to a remote controller that can be used by a person to cause the controller 116 to adjust and / or actuate the valve 106. In some embodiments, such a remote controller directly adjusts and / or actuates the valve 106. Additionally or alternatively, in some embodiments, the controller 116 and / or other actuators for the valve 106 are communicatively coupled to a thermostat or other environmental sensor (e.g., a hygrometer) to automatically adjust and / or operate the valve 106 without human intervention (e.g., after parameters for the thermostat and / or other sensors are set).

[0039]

[0073] The valve 118 in the embodiment shown in Figures 29-31 is similar to that of Figures 23-28. However, the baffle 110 of Figures 23-28 is omitted and the valve 118 extends completely across the cross-sectional area of ​​the air duct 14. Additionally, as shown in the illustrated embodiment, the valve 118 includes four pivoting flaps 120 instead of only two. Each flap 120 is hinged to a spoke 36 such that the valve 118 can be selectively moved between a fully closed position (e.g., as shown in the embodiment of Figure 29), a partially open position (e.g., as shown in the embodiment of Figure 30), and a fully open position (e.g., as shown in the embodiment of Figure 31).

[0040]

[0074] The embodiment of the valve 122 shown in Figures 32-34 is similar to the valve 118 of Figures 29-31, but includes eight flaps 124 instead of four. In this embodiment, each spoke 36 is pivotally connected to two flaps 124. The valve 122 can be selectively moved to a fully closed position (e.g., as shown in the embodiment of Figure 32), a partially open position (e.g., as shown in the embodiment of Figure 33), and a fully open position (e.g., as shown in the embodiment of Figure 34). It should be noted that the frame 12 can have virtually any number of spokes 36 and virtually any number of valve flaps 124.

[0041]

[0075] In the illustrated embodiment of FIGS. 35-37, the valve 126 includes an iris diaphragm attached to the frame 12 and defines a centrally located, variable-sized opening 128 through which air 20 passes. In this embodiment, the valve 126 includes a plurality of relatively raised leaves 130 that, when pivoted by rotating an outer ring 132, move the leaves to adjust the central opening 128. In some embodiments, the position and / or movement of the leaves 130 are controlled by a controller and / or other actuators similar to the controller 116 described above in connection with FIG. 26. In some embodiments, the controller and / or other actuators are controlled by a human, via a remote control, and / or by a thermostat or other environmental sensor (e.g., a hygrometer). FIG. 35 shows the valve 126 fully closed, FIG. 36 shows the valve 126 partially open, and FIG. 37 shows the valve 126 fully open.

[0042]

[0076] In some embodiments, other types of HVAC components can be installed with the air duct system, such as, for example, an air filter. In some embodiments, the air filter is shaped to substantially fill the intersection area of ​​the air duct such that air in the air duct passes through the filter. More specifically, in some such embodiments, the air filter is attached to one of the hoops 32 and fills the opening defined by the hoop 32. In other embodiments, a rectangular or square air filter is attached to one of the hoops 32. In some such embodiments, one or more baffles can be used to fill the space between the rectangular filter and the circular hoop 32. Additionally or alternatively, in some embodiments, the HVAC components include one or more fans. In some embodiments, the fan is housed in a cylindrical housing substantially the same size as the hoop 32 and is attached to and supported by the hoop. In some embodiments, the fan (and / or corresponding housing) may be significantly smaller than the diameter of the hoop 32. In some embodiments, the operation, speed and / or direction of such fans are controlled by a controller and / or other actuators similar to controller 116 described above in connection with Figure 26. In some embodiments, the controller and / or other actuators are controlled by a human via a remote control and / or by a thermostat or other environmental sensor (e.g., a hygrometer).

[0043]

[0077] From the above, it will be appreciated that example methods, apparatus, and articles are disclosed that enable a multi-purpose airflow system that includes multiple airflow geometries using cross sections such as elbows and T-shaped sections, as well as a variety of capabilities including turbulence reduction, humidification, heating, and airflow restriction. The examples disclosed herein include structures that support fabric ducts and allow for control (e.g., via valves), monitoring (e.g., via sensors), and regulation (e.g., via resistance wires) of the fluids conveyed therein, without the condensation, drafts, and losses associated with metal ducts.

[0044]

[0078] The terms "including" and "comprising" (and all forms and tenses thereof) are used herein as open-ended terms. Thus, whenever a claim uses any form of "comprising" or "comprising" (e.g., comprises, includes, comprises, includes, has, etc.) as a preamble or within the scope of any type of claim recitation, it should be understood that additional elements, terms, etc. may be present without being outside the scope of the corresponding claim or recitation. As used herein, when the phrase "at least" is used as a transitional term, for example, in the preamble of a claim, it is open-ended in the same way that the terms "comprising" and "including" are open-ended. The term "and / or," when used in a form such as, for example, A, B, and / or C, refers to any combination or subset of (1) A only, (2) B only, (3) C only, (4) A and B, (5) A and C, (6) B and C, and (7) A, B, and C. When used herein in the context of describing a structure, component, item, object, and / or thing, the phrase "at least one of A and B" is intended to refer to an implementation that includes either (1) at least one A, (2) at least one B, and (3) at least one A and at least one B. Similarly, when used herein in the context of describing a structure, component, item, object, and / or thing, the phrase "at least one of A or B" is intended to refer to an implementation that includes either (1) at least one A, (2) at least one B, and (3) at least one A and at least one B. When used herein in the context of describing the execution or performance of a process, instruction, action, activity, and / or step, the phrase "at least one of A and B" is intended to refer to an implementation that includes either (1) at least one A, (2) at least one B, and (3) at least one A and at least one B.Similarly, when used herein in the context of describing the execution or performance of a process, instruction, action, activity, and / or step, the phrase "at least one of A or B" is intended to refer to an implementation that includes either (1) at least one A, (2) at least one B, and (3) at least one A and at least one B.

[0045]

[0079] As used herein, singular references (e.g., "a", "an", "first", "second", etc.) do not exclude a plurality. The term "a" or "an" entity as used herein refers to one or more of that entity. The terms "a" (or "an"), "one or more", and "at least one" can be used interchangeably herein. Furthermore, although individually listed, a plurality of means, elements or method actions may be performed by, for example, a single unit or processor. Furthermore, although individual features may be included in different embodiments or claims, these may be combined, and inclusion in different embodiments or claims does not imply that a combination of features is not feasible and / or advantageous.

[0046]

[0080] Example 1 includes an air duct system including an air duct having an elongated tubular wall of a pliable material, a frame arrangeable inside the tubular wall of the air duct, an air duct hoop for radially supporting the tubular wall, the hoop defining an opening for providing an air flow passage along the length of the air duct, an HVAC component arrangeable inside the tubular wall of the air duct, the HVAC component attached and supported by the frame inside the air duct, and an HVAC component for adjusting a characteristic of the air.

[0047]

[0081] Example 2 includes the air duct system of example 1, wherein the HVAC component includes a baffle covering at least a portion of the opening in the hoop.

[0048]

[0082] Example 3 includes the air duct system of example 2, wherein the baffle has a circular shape centered on the central axis of the tubular wall.

[0049]

[0083] Example 4 includes the air duct system of Example 3, wherein the baffles are positioned along the periphery of the opening adjacent the hoop spaced from the central axis.

[0050]

[0084] Example 5 includes the air duct system of example 3, wherein the baffle is positioned adjacent the central axis and spaced from the hoop.

[0051]

[0085] Example 6 includes the air duct system of example 2, wherein the portion of the opening covered by the baffle is a first portion and the HVAC component further includes a valve for controlling airflow through a second portion of the opening in the hoop, the second portion being different from the first portion.

[0052]

[0086] Example 7 includes the air duct system of Example 1, wherein the HVAC component includes a valve for controlling air flow through the opening in the hoop.

[0053]

[0087] Example 8 includes the air duct system of example 1, where the HVAC component includes an air straightener.

[0054]

[0088] Example 9 includes an air duct system including an air duct having a tubular wall of a pliable material, the air duct elongated in a longitudinal direction, a frame including a hoop arrangeable within the air duct to support the tubular wall in a radial direction perpendicular to the longitudinal direction, the hoop being less flexible than the pliable material, the hoop defining a fully open airflow area extending substantially perpendicular to the longitudinal direction, an HVAC component mounted to the frame within the air duct, the HVAC component regulating the flow of air through the air duct.

[0055]

[0089] Example 10 includes the air duct system of example 9, wherein the HVAC component includes a baffle, the baffle extending radially to provide a flow restriction defining a partially open airflow area perpendicular to the longitudinal direction, the flow restriction being substantially centered radially within the air duct.

[0056]

[0090] Example 11 includes the air duct system of Example 10, wherein the partially open airflow area is defined by the hoop and the perimeter of the baffle.

[0057]

[0091] Example 12 includes the air duct system of example 10, wherein the partially open airflow area is defined at least in part by an inner perimeter of the baffle.

[0058]

[0092] Example 13 includes the air duct system of Example 10, where the baffle is less flexible than the pliable material of the tubular wall.

[0059]

[0093] Example 14 includes the air duct system of Example 10 where the baffle is a perforated plate.

[0060]

[0094] Example 15 includes the air duct system of Example 10, where the baffle is a screen.

[0061]

[0095] Example 16 includes the air duct system of example 10, further including a valve providing an adjustable flow restriction, the valve mounted to the frame adjacent the baffle.

[0062]

[0096] Example 17 includes the air duct system of Example 10, where the partially open airflow area is less than 80% of the fully open airflow area.

[0063]

[0097] Example 18 includes an air duct system including an air duct having a tubular wall of a flexible material, the air duct being elongated in a longitudinal direction, a hoop arrangeable within the air duct to support the tubular wall in a radial direction perpendicular to the longitudinal direction, the hoop being less flexible than the flexible material, a frame including the hoop and a hanger connected to at least one of the frame or the tubular wall, the hanger supporting the air duct in a suspension, and an HVAC component attached to the frame inside the air duct, the HVAC component regulating the flow of air through the air duct.

[0064]

[0098] Example 19 includes the air duct system of example 18, wherein the HVAC component includes a valve mounted to the frame inside the air duct, the valve providing an adjustable flow restriction through which the air flows.

[0065]

[0099] Example 20 includes the air duct system of example 19, wherein the valve includes a plurality of flaps, each of which is pivotable relative to the frame.

[0066]

[0100] Example 21 includes the air duct system of example 19, wherein the valve includes an iris diaphragm defining a variable opening radially centered within the air duct.

[0067]

[0101] Example 22 includes the air duct system of example 19, and further includes an electrical controller mounted to the frame and operatively connected to the valve for adjusting the adjustable flow restriction.

[0068]

[0102] Example 23 includes the air duct system of example 22, wherein the air duct includes a T-shaped section defining a plurality of air flow branches, and the control device is in the T-shaped region.

[0069]

[0103] Example 24 includes the air duct system of example 22, wherein the air duct includes a manifold defining a plurality of air flow branches, and the control device is in the manifold.

[0070]

[0104] Example 25 includes an air duct system including an air duct having a tubular wall of a flexible material and elongated in a longitudinal direction, a hoop arrangeable inside the air duct to support the tubular wall in a radial direction perpendicular to the longitudinal direction, the hoop being less flexible than the flexible material, and an air flow guide vane attached to and supported by the hoop, the air flow guide vane having a leading edge and a trailing edge, the leading edge being upstream of the trailing edge with respect to air flow through the air duct, the air flow guide vane having a guide surface extending from the leading edge to the trailing edge, the guide surface extending generally parallel to the longitudinal direction for directing the air flow in the longitudinal direction.

[0071]

[0105] Example 26 includes the air duct system of Example 25, wherein the air flow guide vanes are less flexible than the pliable material of the tubular wall.

[0072]

[0106] Example 27 includes the air duct system of example 25, further including a plurality of air flow guide vanes, the air flow guide vanes being substantially parallel to one another.

[0073]

[0107] Example 28 includes the air duct system of example 25, wherein the guide surface is substantially planar.

[0074]

[0108] Example 29 includes the air duct system of example 25, in which the guide surface is curved.

[0075]

[0109] Example 30 includes the air duct system of example 25, wherein the air duct includes an elbow portion, the air flow guide vanes are arranged inside the elbow portion, and the guide surface is curved.

[0076]

[0110] Example 31 includes the air duct system of example 25, where the hoop is a first hoop, and the air duct system further includes a frame including the first hoop, a second hoop arrangeable inside the air duct, and a shaft, the second hoop spaced apart from the first hoop, and the shaft connecting the first hoop and the second hoop.

[0077]

[0111] Example 32 includes the air duct system of example 31, further including a hanger connected to at least one of the frame or the tubular wall to support the air duct in a suspended state.

[0078]

[0112] Example 33 includes the air duct system of example 31, wherein the air flow guide vanes extend a distance between the first hoop and the second hoop.

[0079]

[0113] Example 34 includes an air duct system including an air duct having a tubular wall of a flexible material, the air duct being elongated in a longitudinal direction, a frame including a hoop arrangeable inside the air duct to support the tubular wall in a radial direction perpendicular to the longitudinal direction, the hoop being less flexible than the flexible material, and a gas sensor attached to the frame and in fluid communication with the air flow within the air duct, the gas sensor providing a feedback signal that changes in response to changing conditions in the air flow.

[0080]

[0114] Example 35 includes the air duct system of Example 34, wherein the hoop is a first hoop, and the frame further includes a second hoop, a shaft connecting the first hoop to the second hoop, and spokes extending radially between the shaft and the first hoop, and the gas sensor is attached to the spokes.

[0081]

[0115] Example 36 includes the air duct system of example 34, wherein the feedback signal is air pressure and the condition that changes is a change in static pressure of the airflow.

[0082]

[0116] Example 37 includes the air duct system of Example 34, wherein the feedback signal is air pressure and the condition that changes is a change in stagnation pressure of the airflow.

[0083]

[0117] Example 38 includes the air duct system of example 34, wherein the feedback signal is electrical and the change condition is a change in temperature of the air flow.

[0084]

[0118] Example 39 includes the air duct system of example 34, wherein the feedback signal is electrical and the condition that changes is a change in humidity of the airflow.

[0085]

[0119] Example 40 includes the air duct system of example 34, wherein the feedback signal is electrical and the condition that changes is a change in the concentration of carbon dioxide in the air stream.

[0086]

[0120] Example 41 includes the air duct system of example 34, wherein the feedback signal is electrical and the changing condition is a change in concentration of smoke in the airflow.

[0087]

[0121] Example 42 includes an air duct system comprising: an air duct having a tubular wall of a flexible material, the air duct being elongated in a longitudinal direction; a frame including a hoop arrangeable inside the air duct to support the tubular wall in a radial direction perpendicular to the longitudinal direction, the frame being less flexible than the flexible material; and a temperature changing device attachable to the frame in a heat transfer relationship with an air flow inside the air duct, the temperature changing device changing a temperature of the air flow as the air flow flows in proximity to the temperature changing device.

[0088]

[0122] Example 43 includes the air duct system of example 42, wherein the temperature changing device is a tube conveying a fluid.

[0089]

[0123] Example 44 includes the air duct system of example 43, wherein the hoop is a first hoop and the frame further includes a second hoop and a shaft for connecting the first hoop and the second hoop, the shaft being hollow to function as a tube.

[0090]

[0124] Example 45 includes the air duct system of example 42, wherein the temperature changing device includes an electrical resistance wire.

[0091]

[0125] Example 46 includes the air duct system of Example 42, wherein the hoop is a first hoop, the frame further includes a second hoop and a shaft connecting the first hoop and the second hoop, the shaft being hollow to act as a conduit, and the temperature changing device includes an electrically resistive wire inside the conduit.

[0092]

[0126] Example 47 includes the air duct system of example 42, wherein the temperature changing device is a heat exchanger including a plurality of fins.

[0093]

[0127] Example 48 includes the air duct system of example 42, wherein the temperature altering device includes a nozzle that emits water into the airflow to alter at least one of a temperature or humidity of the airflow.

[0094]

[0128] Although certain example methods, apparatus, and articles of manufacture have been described herein, the scope of coverage of this patent is not limited thereto. On the contrary, this patent covers all methods, apparatus, and articles of manufacture fairly falling within the scope of the appended claims, either literally or under the doctrine of equivalents.

Claims

1. 1. An air duct system comprising: an air duct having an elongated tubular wall of a flexible material; a frame positionable inside the tubular wall of the air duct, the frame including a hoop for radially supporting the tubular wall, the hoop defining an opening providing a passage for air flow along a length of the air duct; an alignable HVAC component within the tubular wall of the air duct, the HVAC component being mounted and supported by the frame inside the air duct for conditioning a characteristic of the air; An air duct system comprising:

2. The air duct system of claim 1 , wherein the HVAC component comprises a baffle covering at least a portion of the opening in the hoop.

3. The air duct system of claim 2 , wherein the baffle has a circular shape centered about a central axis of the tubular wall.

4. The air duct system of claim 3 , wherein the baffle is to be positioned along a periphery of the opening adjacent the hoop away from the central axis.

5. The air duct system of claim 3 , wherein said baffle is spaced from said hoop adjacent said central axis.

6. 3. The air duct system of claim 2, wherein the portion of the opening covered by the baffle is a first portion, and the HVAC component further includes a valve for controlling air flow through a second portion of the opening in the hoop, the second portion being different from the first portion.

7. The air duct system of claim 1 , wherein the HVAC component includes a valve that controls the flow of air through an opening in the hoop.

8. The air duct system of claim 1 , wherein the HVAC component comprises an air straightener.

9. 1. An air duct system comprising: a longitudinally elongated air duct having a tubular wall of a pliable material; a frame including a hoop arrangeable inside the air duct for radially supporting a tubular wall perpendicular to the longitudinal direction, the hoop being less flexible than the pliable material, the hoop defining a fully open air flow area extending substantially perpendicular to the longitudinal direction; an HVAC component mounted to the frame inside the air duct, the HVAC component regulating the flow of air through the air duct; An air duct system comprising:

10. 10. The air duct system of claim 9, wherein the HVAC component includes a baffle extending radially to provide a flow restriction defining a partially open airflow area perpendicular to the longitudinal direction, the flow restriction being substantially centered within the air duct with respect to the radial direction.

11. The air duct system of claim 10 , wherein the partially open airflow area is defined by the hoop and a perimeter of the baffle.

12. The air duct system of claim 10 , wherein the partially open airflow area is defined at least in part by an inner periphery of the baffle.

13. The air duct system of claim 10 , wherein the baffle is less flexible than the pliable material of the tubular wall.

14. The air duct system of claim 10 , wherein the baffle is a perforated plate.

15. The air duct system of claim 10 , wherein the baffle is a screen.

16. The air duct system of claim 10 further comprising a valve providing an adjustable flow restriction, said valve mounted to said frame adjacent said baffle.

17. 11. The air duct system of claim 10, wherein the partially open airflow area is less than 80% of the fully open airflow area.

18. 1. An air duct system comprising: a longitudinally elongated air duct having a tubular wall of a pliable material; a hoop disposable inside the air duct for supporting a tubular wall in a radial direction perpendicular to the longitudinal direction, the hoop being less flexible than the pliable material; and a frame including the hoop; a hanger connected to at least one of the frame or the tubular wall, the hanger supporting the air duct in a suspended state; an HVAC component mounted to the frame inside the air duct, the HVAC component regulating the flow of air through the air duct; An air duct system comprising:

19. 20. The air duct system of claim 18, wherein the HVAC component includes a valve mounted to the frame inside the air duct, the valve providing an adjustable flow restriction for air flow therethrough.

20. 20. The air duct system of claim 19, wherein the valve includes a plurality of flaps, each of which is pivotally adjustable relative to the frame.

21. 20. The air duct system of claim 19, wherein the valve includes an iris diaphragm defining a variable opening centered within the air duct in the radial direction.

22. 20. The air duct system of claim 19, further comprising an electrical controller mounted to said frame and operably connected to said valve for adjusting said adjustable flow restriction.

23. 23. The air duct system of claim 22, wherein the air duct includes a T-section defining a plurality of airflow branches, and the control device is in the T-section.

24. 23. The air duct system of claim 22, wherein the air duct includes a manifold defining a plurality of airflow branches, and the control device is in the manifold.

25. 1. An air duct system comprising: a longitudinally elongated air duct having a tubular wall of a pliable material; a hoop disposable inside the air duct for supporting the tubular wall in a radial direction perpendicular to the longitudinal direction, the hoop being less flexible than the pliable material; and an airflow guide vane attached to and supported by the hoop, the airflow guide vane having a leading edge and a trailing edge, the leading edge being upstream of the trailing edge with respect to an air flow through the air duct, the airflow guide vane having a guide surface extending from the leading edge to the trailing edge, the guide surface extending generally parallel to the longitudinal direction to direct the air flow in the longitudinal direction; An air duct system comprising:

26. 26. The air duct system of claim 25, wherein the air flow guide vanes are less flexible than the pliable material of the tubular wall.

27. 26. The air duct system of claim 25, further comprising a plurality of air flow guide vanes, said air flow guide vanes being substantially parallel to one another.

28. 26. The air duct system of claim 25, wherein the guide surface is substantially flat.

29. 26. The air duct system of claim 25, wherein the guide surface is curved.

30. 26. The air duct system of claim 25, wherein the air duct has an elbow section, the air flow guide vanes are disposed within the elbow section, and the guide surfaces are curved.

31. 26. The air duct system of claim 25, wherein the hoop is a first hoop, and the air duct system further includes a frame including the first hoop, a second hoop arrangeable inside the air duct, and a shaft, the second hoop being spaced apart from the first hoop, and the shaft connecting the first hoop and the second hoop.

32. 32. The air duct system of claim 31, further comprising a hanger connected to at least one of the frame or the tubular wall to provide suspension support for the air duct.

33. 32. The air duct system of claim 31, wherein the air flow guide vanes extend a distance between the first hoop and the second hoop.

34. 1. An air duct system comprising: a longitudinally elongated air duct having a tubular wall of a pliable material; a frame including a hoop arrangeable inside the air duct for supporting a tubular wall in a radial direction perpendicular to the longitudinal direction, the hoop being less flexible than the pliable material; a gas sensor mounted to the frame in fluid communication with the air flow within the air duct, the gas sensor providing a feedback signal that varies in response to changing conditions in the air flow; An air duct system comprising:

35. 35. The air duct system of claim 34, wherein the hoop is a first hoop, the frame further includes a second hoop, a shaft connecting the first hoop to the second hoop, and spokes extending radially between the shaft and the first hoop, the gas sensor being attached to the spokes.

36. 35. The air duct system of claim 34, wherein the feedback signal is air pressure and the changing condition is a change in static pressure of the air flow.

37. 35. The air duct system of claim 34, wherein said feedback signal is air pressure and said changing condition is a change in stagnation pressure of the air flow.

38. 35. The air duct system of claim 34, wherein the feedback signal is electrical and the changing condition is a change in temperature of the air stream.

39. 35. The air duct system of claim 34, wherein the feedback signal is electrical and the changing condition is a humidity change in the air stream.

40. 35. The air duct system of claim 34, wherein the feedback signal is electrical and the changing condition is a change in carbon dioxide concentration in the air stream.

41. 35. The air duct system of claim 34, wherein the feedback signal is electrical and the changing condition is a change in smoke concentration within the air stream.

42. 1. An air duct system comprising: a longitudinally elongated air duct having a tubular wall of a pliable material; a frame including a hoop arrangeable inside the air duct for supporting a tubular wall in a radial direction perpendicular to a longitudinal direction, the hoop being less flexible than the pliable material; a temperature modifying device mountable to the frame in heat transfer relationship with the flow of air inside the air duct, the temperature modifying device changing a temperature of the flow of air as the flow of air flows proximate to the temperature modifying device; An air duct system comprising:

43. 43. The air duct system of claim 42, wherein the temperature changing device is a tube carrying a fluid.

44. 44. The air duct system of claim 43, wherein the hoop is a first hoop and the frame further includes a second hoop and a shaft for connecting the first hoop and the second hoop, the shaft being hollow to function as the tube.

45. 43. The air duct system of claim 42, wherein the temperature altering device comprises an electrical resistive wire.

46. 43. The air duct system of claim 42, wherein the hoop is a first hoop, the frame further includes a shaft for connecting the first hoop and the second hoop, the shaft being hollow to act as a conduit, and the temperature changing device includes an electrical resistance wire inside the conduit.

47. 43. The air duct system of claim 42, wherein the temperature changing device is a heat exchanger including a plurality of fins.

48. 43. The air duct system of claim 42, wherein the temperature altering device includes a nozzle that emits water into the air flow to alter at least one of a temperature or humidity of the air flow.

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