Air damper

Abstract

An air damper assembly for an air duct having an interior wall and an exterior wall is provided. The air damper assembly includes a damper plate having a periphery and multiple teeth spaced at least partially around and extending from the periphery. The multiple teeth vary in length from a maximum to a minimum over a span of approximately 90 degrees around the periphery. The air damper assembly further includes an axle assembly fixedly coupled to the damper plate and rotatably coupled to the air duct. Rotation of the axle assembly causes the damper plate to rotate within the air duct between a fully open position and a fully closed position to increase or decrease a flow of fluid through the air duct.

Description

BACKGROUND

[0001] The present invention relates, in exemplary embodiments, to air duct dampers and air duct airflow sensors. More particularly, exemplary embodiments relate to air dampers with controllable resolution at lower flow rates.

[0002] Air dampers are mechanical valves used to permit, block, and control the flow of air in air ducts. Conventional dampers typically comprise a circular blade having an axle passing through the diameter of the blade, the ends of the axle being rotatingly mounted in the air duct wall. The diameter of the blade is marginally smaller than the diameter of the circular (or other cross-sectional shape) air duct so that, when the blade is in the closed position, all, or essentially all airflow is blocked, with no air passing between the edge of the blade and the air duct interior wall. A motor or other control mechanism is associated with the axle and, when actuated, rotates the axle, which causes the blade to rotate between an open, closed, or partially open position so as to permit controllable flow of air through the duct. A sensor or multiple sensors are disposed proximate to the damper for measuring airflow. The sensor is connected to a processor, which actuates the motor that controls the blade rotation, thus controlling the airflow required.

[0003] For many uses, conventional dampers are sufficient. However, air ducts used in certain critical room environments, for example, with exhaust valves, supply valves, room balance systems, and the like, require accurate control of airflow, particularly when the static pressure in the ductwork is high, tiny movements of the blade damper can result in significant changes in airflows. When a conventional damper blade is rotated from an initial closed position to a slightly open position, there is a tendency for a large volume of air to immediately be allowed to pass through the damper area, such volume being relatively uncontrollable. When the static pressure in the ductwork is high even tiny movements of the blade damper can result in significant changes in airflow. There is not enough control over the blade with the actuator to create movements small enough that proper control is maintained. It would be desirable to have a damper blade that would permit a more controllable flow of air at the nearly closed (or nearly open) position; i.e., at lower airflow requirements and more so at higher pressures.

[0004] It would further be desirable to have an airflow sensor that would not be dependent on airflow orientation so as to permit location of sensor closer to a bend in the air duct than conventional sensors can be positioned. It would be desirable to have an airflow sensor less susceptible to clogging. US2017 / 0248237 discloses a damper plate for use in an air damper assembly for an air duct. The damper plate comprises a periphery having a plurality of teeth.SUMMARY

[0005] One implementation of the present disclosure is a damper plate according to claim 1.

[0006] In some embodiments, the damper plate includes a first airfoil member having multiple teeth made of a first material; and a second airfoil member having multiple teeth made of second material, the second material having a greater stiffness than the first material. In other embodiments, the damper plate further includes a third airfoil member having multiple teeth made of a third material, the third material having a greater stiffness than the second material.

[0007] In some embodiments, each of the teeth includes a resilient portion proximate the periphery and a flexible portion. The resilient portion has a greater stiffness than the flexible portion.

[0008] In some embodiments, the damper plate includes a gasket configured to contact the interior wall of the air duct when the damper plate is in the fully closed position.

[0009] In some embodiments, a portion of the multiple teeth contact the interior wall of the air duct when the damper plate is in the fully closed position. In some embodiments, a portion of the multiple teeth contact the interior wall of the air duct when the damper plate is in a partially closed position.

[0010] In some embodiments, a portion of the multiple teeth are fabricated from polytetrafluoroethylene (Teflon). In some embodiments, a portion of the multiple teeth are fabricated from a metal having a plastic coating.

[0011] In some embodiments, the axle assembly includes a first shaft member and a second shaft member. Each of the first shaft member and the second shaft member includes a slot configured to receive the damper plate.

[0012] In some embodiments, the axle assembly includes a shaft member configured to be fastened to the damper plate using a bracket component and multiple rivets.

[0013] In some embodiments, the air damper assembly includes a damper control assembly configured to drive rotation of the axle assembly. In other embodiments, the damper control assembly comprises a pressure sensor, a motor, and an actuator.

[0014] Another implementation of the present disclosure is a method for controlling a flow of fluid through an air duct according to claim 9. minimum over a span of approximately 90 degrees around the periphery. The method further includes driving the damper plate to the position setpoint.

[0015] In some embodiments, a portion of the multiple teeth contact the interior wall of the air duct when the damper plate is in the fully closed position. In some embodiments, a portion of the multiple teeth contact the interior wall of the air duct when the damper plate is in a partially closed position.

[0016] In some embodiments, the damper plate includes a first airfoil member having multiple teeth made of a first material; and a second airfoil member having multiple teeth made of second material, the second material having a greater stiffness than the first material. In other embodiments, the damper plate further includes a third airfoil member having multiple teeth made of a third material, the third material having a greater stiffness than the second material.

[0017] In some embodiments, each of the teeth includes a resilient portion proximate the periphery and a flexible portion. The resilient portion has a greater stiffness than the flexible portion.BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings disclose exemplary embodiments in which like reference characters designate the same or similar parts throughout the figures of which: FIG. 1 is an isometric view of an air duct assembly, according to some embodiments. FIG. 2 is an exploded isometric view of an air damper assembly which can be used in the air duct assembly of FIG. 1, according to some embodiments. FIG. 3 is a front elevation view of the air damper assembly of FIG. 2, according to some embodiments. FIG. 4 is a side elevation view of the air damper assembly of FIG. 2, according to some embodiments. FIG. 5 is a rear elevation view of the air damper assembly of FIG. 2, according to some embodiments. FIG. 6 is a side cross-sectional view of a shaft arrangement which can be used in the air damper assembly of FIG. 2, according to some embodiments. FIG. 7 is a side cross-sectional view of another shaft arrangement which can be used in the air damper assembly of FIG. 2, according to some embodiments. FIG. 8 is a side cross-sectional view of the air duct assembly of FIG. 1, according to some embodiments. FIG. 9 is a detail cross-sectional view that depicts the air damper assembly of FIG. 2 in a partially closed position, according to some embodiments. FIG. 10 is a detail cross-sectional view that depicts the air damper assembly of FIG. 2 in a fully closed position, according to some embodiments. FIG. 11 is front elevation view of another air damper assembly which can be used in the air duct assembly of FIG. 1, according to some embodiments. FIG. 12 is side elevation view of the air damper assembly of FIG. 11, according to some embodiments. FIG. 13 is a side elevation view of another air damper assembly that can be used in the air duct assembly of FIG. 1, according to some embodiments. FIG. 14 is an exploded isometric view of another air damper assembly which can be used in the air duct assembly of FIG. 1, according to some embodiments. FIG. 15 is a detail view of another air damper assembly which can be used in the air duct assembly of FIG. 1, according to some embodiments. FIG. 16 is a side cross-sectional view of an air duct airflow sensor assembly, according to some embodiments. FIG. 17 is a side cutaway view of the air duct assembly of FIG. 1, according to some embodiments. FIG. 18 is a top elevation view of the air duct assembly of FIG. 1, according to some embodiments. FIG. 19 is an exploded perspective view of an air duct, ring and gasket components that can be utilized in the air duct assembly of FIG. 1, according to some embodiments. FIG. 20 is another top view of the air duct assembly of FIG. 1, according to some embodiments. FIG. 21 is a side cross-sectional view of the air duct assembly taken along the line B-B of FIG. 20, according to some embodiments. FIG. 22 is a detail view C-C of the nipple, gasket and tube, according to some embodiments. FIG. 23 is a detail view D-D of the gasket, according to some embodiments. FIG. 24 is a side cross-sectional view of another air duct airflow sensor assembly, according to some embodiments. FIG. 25 is a side cross-sectional view of another air duct airflow sensor assembly, according to some embodiments. DETAILED DESCRIPTION

[0019] Unless otherwise indicated, the drawings are intended to be read (for example, cross-hatching, arrangement of parts, proportion, degree, or the like) together with the specification, and are to be considered a portion of the entire written description of this invention. As used in the following description, the terms "horizontal", "vertical", "left", "right", "up" and "down", "upper" and "lower" as well as adjectival and adverbial derivatives thereof (for example, "horizontally", "upwardly", or the like), simply refer to the orientation of the illustrated structure as the particular drawing figure faces the reader. Similarly, the terms "inwardly" and "outwardly" generally refer to the orientation of a surface relative to its axis of elongation, or axis of rotation, as appropriate.

[0020] FIG. 1 depicts an isometric view of a cylindrical air duct assembly 1. As shown, the air duct assembly 1 includes a first end 2, a second end 3, and interior wall 4, an exterior wall 5, and a control assembly 100. In some embodiments, the air duct assembly 1 can be situated such that air flows from the first end 2 to the second end 3. Air duct assembly 1 is further shown to include an air damper assembly 10 situated within the interior wall 4.

[0021] Referring now to FIGS. 2-5, several views of the air damper assembly 10 are provided. FIG. 2 depicts an exploded isometric view, FIG. 3 depicts a front elevation view, FIG. 4 depicts a side elevation view, and FIG. 5 depicts a rear elevation view. Damper assembly 10 is shown to include, among other components, a first damper plate 12, and a second damper plate 14. A first airflow member comprises a first section 18 and a second section 20. In exemplary embodiments, the first and second sections 18, 20 are made of a generally rigid material, such as, but not limited to, metal, polymer, ceramic, wood, coated material, laminate, or the like. Each section comprises a straight portion 22 and a curved portion 24.

[0022] A plurality of fingers 30 is shown to extend outward from and at least partially around the curved peripheral portion of each section 18, 20. In one exemplary embodiment, the fingers 30 may be integrally formed with the sections 18, 20. In another exemplary embodiment, the fingers 30 may be separate and mounted or attached to at least a portion of each section 18, 20. In exemplary embodiments the fingers 30 are formed of a relatively resilient material. In exemplary embodiments, the material may be metal, resilient plastic, or other generally resilient material. In some embodiments, fingers 30 are made of metal or other resilient material which is covered or coated with plastic or other material that will not appreciably scratch the interior wall of the air duct. In other embodiments, fingers 30 are made of a single material that is both resilient and that will not appreciably scratch the interior wall of the air duct.

[0023] The fingers 30 may be sized to have a length smaller proximate to the straight portion 22 and increase in length proximate to the midpoint of the curved portion 24. Stated differently, in such exemplary embodiments, the length of the fingers 30 varies from a maximum to a minimum over a span of about 90 degrees around the periphery. For example, referring specifically to FIG. 2, fingers 31-33 (with finger 31 being longer than fingers 32 or 33) are longer than fingers 34-36 (with finger 34 being longer than fingers 35 or 36). In exemplary embodiments, the second section 20 of the airfoil member 16 is configured in mirror image to the first section 18 and has fingers 30 sized and configured similar to those associated with the first section 18.

[0024] The second airfoil member comprises, in exemplary embodiments, a first section 42 and a second section 44. In exemplary embodiments, the first and second sections 42, 44 are made of a generally rigid material, such as, but not limited to, metal (e.g., Aluminum), polymer, ceramic, wood, coated material, laminate, or the like. In some embodiments, the first and second sections 42, 44 are fabricated from different material as first and second sections 18, 20. For example, the first and second sections 42, 44 can be fabricated from a material of lower stiffness than the material of first and second sections 18, 20. In other embodiments, the first and second sections 42, 44 are fabricated from the same material as first and second sections 18, 20. Each section 42, 44 is shown to comprise a straight portion 46 and a curved portion 48.

[0025] A plurality of fingers 50 extends outward from and at least partially around the curved peripheral portion of each section 42, 44. In one exemplary embodiment, the fingers 50 may be integrally formed with sections 42, 44. In another exemplary embodiment, the fingers 50 may be separate and mounted or attached to at least a portion of each section 42, 44. In exemplary embodiments, the fingers 50 are formed of a material more flexible than the material forming the fingers 30. In exemplary embodiments, the material may be a flexible metal, plastic, fabric, laminate, or other material having a degree of flexion but which can return to the unflexed position. In one exemplary embodiment, the material may be polytetrafluorenthylene ("Teflon ®< ). Similar to the fingers 30, in some embodiments, the fingers 50 are sized to have a length smaller proximate to the straight portion 46 and increase in length proximate to the midpoint of the curved portion 48. For example, fingers 51-53 (with finger 51 being longer than fingers 52 or 53) are longer than fingers 54-56 (with finger 54 being longer than fingers 55 or 56).

[0026] In exemplary embodiments, the second section 44 is configured in mirror image to the first section 42 and has fingers 50 sized and configured similar to those associated with the first section 42. In exemplary embodiments, the fingers 50 may be sized to be slightly longer and / or slightly larger than the corresponding matching adjacent fingers 30 (i.e., when the first and second airfoil members are assembled and the fingers 30 are generally adjacent to fingers 50, finger 31 is adjacent to finger 51). This may be done so that the resilient fingers 30 are close to, but not touching (or barely touching) the interior wall 4 of the air duct 1 when the damper 10 is in the closed position, which will avoid or reduce the likelihood of the interior wall 4 being scratched by the resilient fingers 30. In an alternative exemplary embodiment, the fingers 30 are slightly offset from the corresponding fingers 50.

[0027] The first and second damper plates 12, 14 may be connected to each other with the first and second airfoil members comprising sections 18, 20, 42, 44 sandwiched therebetween such that on one side of the damper the fingers 50 are showing on the top half and the fingers 30 are showing on the bottom half, with the reverse being the case on the other side of the damper. In some embodiments, the sections 18, 20, 42, 44 may be coupled with each other and the damper plates 12, 14 using rivets 58. In other embodiments, any other suitable fastening mechanism (e.g., bolts, screws, adhesives) can be utilized to couple the sections 18, 20, 42, 44 and the damper plates 12, 14. In some embodiments, the first and second damper plates 12, 14, may be connected to each other and the axle assembly 70 connected thereto using one or more bolts 82 and locknuts 84. It is to be understood that other fastening mechanisms known to those skilled in the air can be used.

[0028] In exemplary embodiments, an optional gasket 60 may be placed between the first and second damper plates 12, 14 and abutting the first and second sections 42, 44 of the second airfoil member (when assembled). The optional gasket 60 can be used to seal off the airflow through the air duct assembly 1. In various embodiments, the optional gasket can be fabricated from rubber, silicone, neoprene, a plastic polymer, or any other suitable gasket material.

[0029] The axle assembly 70 may comprise a single piece, or, in exemplary embodiments, may comprise a first member 72 and a second member 74. In exemplary embodiments, the first member 72 may be longer than the second member 74. As described in greater detail below with reference to FIG. 8, this may be because the first member 72 is configured to couple with a motor within the control assembly 100 of the air duct damper assembly 1. In some embodiments, each shaft member 72, 74 may comprise a split shaft sized to fit over the assembled first and second damper plates 12, 14 and first and second airfoil members, as shown in FIGS. 3-5. In other words, each shaft member 72, 74 can include a slot to receive the assembled damper plates 12, 14 and airfoil members. In exemplary embodiments, a rotation bushing 76 and a stationary bushing 78 may be fitted over each shaft member 72, 74 to ensure the free rotation of the air damper assembly 10 within the air duct assembly 1. In some embodiments, an O-ring 80 may also be fitted over each shaft member 72, 74.

[0030] Referring now to FIGS. 6 and 7, cross-sectional views of embodiments of the joint between the axle assembly 70, the damper plates 12, 14, and the sections 18, 20, 42, 44 are depicted. For example, as depicted in FIG. 6, the sections 18, 20, 42, and 44 can be retained between the damper plates 12 and 14 using split shaft members 72, 74. In various embodiments, rivets 58 passing through the split shaft members 72, 72 are used to fasten the split shaft members 72, 74 and retain the sections 18, 20, 42, and 44, and the damper plates 12 and 14 in a stacked configuration. In other embodiments, another type of fastener can be utilized instead of rivets 58.

[0031] Referring now to FIG. 7, an alternate joint embodiment is depicted. As shown, a solid shaft 86 may be used in the axle assembly 70 instead of split shaft members 72, 74. The solid shaft 86 may be retained on the stacked configuration of sections 18, 20, 42, 44 and damper plates 12, 14 using a U-bracket 88 and rivets 58. U-bracket 88 can have any suitable geometry required to retain the solid shaft 86 on the stacked configuration. In various embodiments, another type of fastener can be utilized instead of rivets 58. As shown, the solid shaft 86 can be coupled flush against the damper plate 12. In other embodiments, a symmetrical configuration may be utilized, and the solid shaft 86 can be coupled flush against the damper plate 14.

[0032] Referring now to FIG. 8, a side cross-sectional view of the damper assembly 10 mounted in the air duct assembly 1 is shown. The axle assembly shaft member 74 may be positioned in an aperture 90 situated at the bottom of the air duct, and shaft member 72 may be positioned within an aperture 92 situated at the top of the air duct, proximate the control assembly 100. The control assembly 100 may have a housing 102. The housing 102 may house a power supply 104, a gear / motor 106, an actuator 108, a control board 110, a pressure sensor 112, and a low pressure pickup 114, and a high pressure pickup 116. The pickups 114, 116 are in communication with pressure sensor mechanisms (not shown) inside the air duct 1, such mechanisms as are known to those skilled in the art.

[0033] In operation, an operator may provide a target airflow setpoint. Pressure sensor 112 may provide information on the current actual airflow calculated from a high pressure pickup 114 and a low pressure pickup 116. High pressure pickup 114 and low pressure pickup 116 can sense air pressure in the air duct flowing form the first end 2 to the second end 3 of the air duct 1. Movement of the damper 10 may occur to equalize the setpoint and actual airflow. Airflow setpoint signals and measured airflow signals may be received by the control board 110, which generates a position setpoint signal sent to the power supply 104, which in turn actuates the motor 106. The motor 106 is operationally associated with the axle assembly shaft member 72, causing it to rotate as needed between a fully opened position and a fully closed position.

[0034] Referring now to FIGS. 9 and 10, detail cross-sectional views of the air damper assembly 10 are depicted in partially closed and fully closed positions, respectively. When the air damper assembly 10 rotates toward a closed position, as specifically depicted in FIG. 9, fingers 50 and gasket 60 come proximate to the interior wall 4. When doing so, the air flow is reduced, but not entirely. The airspace 120 between the fingers 50 permits air to flow through until the air damper 10 rotates into a fully closed position, in which event the fingers 50 (all or at least a portion thereof), can flex so that most of the length, or at least a portion of the flat surface, of the finger 50 contacts the interior wall 4, as shown in FIG. 10. The larger the portion of the finger 50 that contacts the interior wall 4, the smaller the airspace 120 and the smaller the amount of air that can flow through the damper.

[0035] A feature of the presently disclosed damper is that the airfoil members provide greater control and resolution of air pressure as the damper 10 and fingers 50, get closer to full closure. Because the present design does not need to accelerate air past vortex shedders (such as those used by a conventional damper product available from Accutrol ™< ), higher flow rates can be obtained.

[0036] Referring now to FIGS. 11 and 12, another embodiment of an air damper assembly 300 is depicted. Air damper assembly 300 can include a single plate, as opposed to the first and second damper plates of air damper assembly 10 as described above. Damper assembly 300 can have two rows of fingers 302, 303 attached to the periphery of the damper assembly 300 by fasteners 304. In another exemplary embodiment depicted in FIG. 13, an air damper assembly 400 can have a single row of a plurality of fingers 402 attached to the periphery of the damper assembly 400 by fasteners 404.

[0037] In another alternative embodiment, the damper can have more than two rows of fingers. In one such embodiment, depicted in FIG. 14, a damper 500 is shown having three rows of fingers. The three rows of fingers can be achieved by incorporating a first airfoil (comprised of first section 18 and second section 20), a second airfoil (comprised of first section 42 and second section 44), and a third airfoil 502, comprised of first section 504 and second section 506. In some embodiments, the fingers of sections 504 and 506 of the third airfoil 502 have greater stiffness than the fingers of sections 18, 20, 42, 44. In other embodiments, one or more of sections 18, 20, 42, and 44 have greater or equivalent stiffness to sections 504 and 506.

[0038] Referring now to FIG. 15, a detail view of another embodiment of an air damper assembly 600 is depicted. Air damper assembly 600 can include teeth fabricated from one or more materials with varying stiffness. For example, each tooth 602 may have a relatively resilient or stiff portion 604 proximate to the base 606 and a relatively flexible portion 608 proximate to the distal end 610 of the tooth 602.

[0039] Referring now to FIGS. 16-23, various views depicting the air duct airflow sensor assembly 1000 are shown, according to some embodiments. Air may flow through the air duct airflow sensor assembly 1000 in the direction indicated by arrow "A" as shown in FIG. 16. The air duct airflow sensor assembly 1000 includes a low pressure detection device and a high pressure detection device. The low pressure detection device comprises a hollow ring 1020 which is mounted to or otherwise associated with the interior wall 4. In some embodiments, the outer diameter of the hollow ring 1020 can range from 0.5 inches to 0.75 inches. In an exemplary embodiment, the outer diameter of the hollow ring 1020 is 0.625 inches. The ring 1020 has a plurality of apertures 1022 defined in the inner periphery 1023 of the ring (versus the outer periphery 1024 which is proximate to the interior wall 4). In exemplary embodiments, the apertures 1022 are disposed in the inner periphery of the ring 1020 such that they are generally orthogonal to the orientation of airflow, so that air flows across the apertures 1022, rather than flowing into the apertures 1022.

[0040] A hollow connector nipple 1028 is connected to an aperture defined in the ring 1020 and an aperture defined in the duct 1. A tube 1032 is connected to the nipple 1028. Air flowing into the apertures 1022 can flow through the ring 1020, into the nipple 1028, and through the tube 1032. The tube 1032 is connected to a pressure sensor 1034 such that the air flowing through the tube 1032 is received and detected by the flow pressure sensor 1034. The ring 1020 serves two purposes: as an air collection device, and as an airflow restriction obstacle, so as to create a measurable pressure differential.

[0041] The air duct 1 further includes multiple apertures 1040 defined therein, the apertures 1040 being arranged generally in a ring-shape around the interior wall 4. A gasket 1042 is associated with the exterior wall 5 and is located generally over the apertures 1040. The gasket 1042 has a recessed area 1043 such that when associated with the exterior wall 5 a chamber 1043 is formed. Detail views of the apertures 1040 and chamber 1043 are specifically depicted in FIGS. 22 and 23.

[0042] A hollow connector nipple 1044 is connected to the gasket 1042. In exemplary embodiments, a gasket guarding ring 1045 may be used and is fitted over the gasket 1042. A tube 1046 is connected to the nipple 1044. The tube 1046 is connected to the pressure sensor 1034. In an alternative exemplary embodiment, a separate pressure sensor (not shown) can be connected to the tube 1046. The apertures 1040, gasket 1042, nipple 1044, tube 1046 and pressure sensor 1034 form a high pressure sensor detection device.

[0043] In exemplary embodiments, the pressure sensor 1034 is part of a control assembly 1006 that controls the opening and closing of a damper 1050. In one exemplary embodiment of a control assembly, specifically depicted in FIG. 21, a housing 1100 is mounted to or otherwise associated with the air duct. A sensor 1034, processor 1102, actuator 1104 and power supply 1106 may be disposed within the housing 1100. A damper 1050 is in operational communication with the actuator 1104.

[0044] In operation, air flowing through the duct 1 in the direction of arrow A first encounters the high pressure detection apertures 1040. A portion of the air enters the apertures 1040 and flows into the chamber 1043. The air then moves into the tube 1046 via the nipple 1044, and then into the pressure sensor 1034. The pressure detected is the "high" pressure in the duct 1, i.e., the pressure upstream from the airflow restrictor which is the ring 1020.

[0045] Air flowing through the duct 1 next flows over the ring 1020 and can enter the apertures 1022 and travel through the nipple 1028 and the tube 1032, and into the pressure sensor 1034. The pressure detected is the "low" pressure in the duct, i.e., the pressure at the point where airflow is restricted by the ring 1020. The differential between the high pressure measurement and the low pressure measurement is an indication of the air velocity through the duct, specifically a scaled square root of the measured pressure (i.e., an application of Bernoulli's principle). The sensor 1034 can send a signal to the control assembly 1006 that in turn can cause the damper 1050 to rotate so as to open or close the air duct 1.

[0046] In exemplary embodiments, the pressure sensor 1034 is a "dead-end" pressure sensor (versus a flow-through sensor); i.e., after the initial pressure is established no further airflow goes through the sensor. This can reduce the chance of the apertures 1022 and 1040 becoming clogged.

[0047] In one exemplary embodiment, for an air duct having a 10 inch diameter, a 0.5 inch diameter ring 1020 was used. With such a construction measurements of 850 CFM (cubic feet per minute) down to 35 CFM were obtainable with a 0.1 in Wg duct static. In other embodiments, a 0.625 inch diameter ring 1020 may be utilized.

[0048] A benefit of the presently described sensor assembly is that because of the ring 1020 design having the apertures 1022 orthogonal to the airflow orientation, air to be diverted into the ring 1020 flows over the apertures 1022, rather than directly into the apertures 1022. This can reduce the likelihood of the apertures 1022 becoming clogged by dust, dirt and debris that accompanies the airstream.

[0049] Another benefit is that the presently disclosed apparatus is not dependent on airflow orientation. Typically, conventional pressure sensor apparatus, such as variable air volume ("VAV") boxes, are dependent on airflow orientation, and having a bend or other transition in the duct in the general area where the sensor can result in inaccurate measurement due to the airflow disruption that naturally occurs proximate to the bend. With the air detection means of the presently disclosed apparatus, which is not airflow orientation dependent, the sensor assembly can be located closer to a bend or other transition in the air duct without affecting pressure measurement. This provides the duct system designer with greater flexibility in designing the placement of the valve assembly.

[0050] Another benefit of the presently described sensor assembly is that it presents minimal obstruction to the airflow and thus allows for greater CFM velocity at lower duct statics. Additionally, in the event any of the apertures 1022 become blocked, it is easy to carry out periodic maintenance by disconnecting the sensor 1034 and introducing a blast of compressed air into the tube 1032 or tube 1046. Any clogging debris will be blown out of the apertures 1022 or 1040, respectively.

[0051] Another benefit of the presently described sensor assembly as part of an overall sensor / controller / damper design is that it can operate off of a 0-10V control signal to provide the desired airflow. This allows a designer or operator to set a required CFM with a linear control signal from a control system.

[0052] Referring now to FIGS. 24 and 25, alternate embodiments for airflow restriction used in the low pressure detection device are depicted. Specifically, FIG. 24 depicts an airflow sensor assembly including a shroud component 1060. In some embodiments, the shroud component 1060 can be ring-shaped, with an interior wall attachment portion 1062, an inclined portion 1064, and an aperture shielding portion 1066, although any suitable shroud configuration or geometry may be utilized. In some embodiments, the aperture shielding portion 1066 extends from the interior wall 4 a distance ranging from 0.5 inches to 0.75 inches.

[0053] The aperture shielding portion 1066 is situated proximate apertures 1022 disposed within the air duct 1. A gasket 1048 is associated with the exterior wall 5 and is located generally over the apertures 1022. In some embodiments, one or more gasket guarding rings (not shown) may be used and fitted over the gaskets 1042, 1048. The gasket 1048 has a recessed area 1049 such that when associated with the exterior wall 5 a chamber 1049 is formed. Air flowing through the duct 1 flows over the interior wall attachment portion 1062, the inclined portion 1064, and the aperture shielding portion 1066 of the shroud component 1060 and can enter the apertures 1022. The air can then travel through the chamber 1049 into the nipple 1028. Similar to the pressure measurement process described above with reference to FIGS. 16-23, after passing through the nipple 1028, the air can travel through a tube and into a pressure sensor for the purpose of controlling an air damper assembly.

[0054] Turning now to FIG. 25, an airflow sensor assembly including a channel feature 1070 is depicted. Similar to the shroud component 1060 described above with reference to FIG. 24, the channel feature 1070 may be utilized as an air restriction feature in place of the hollow ring 1020 described above with reference to FIGS. 16-23. The channel feature 1070 can include multiple apertures 1022 distributed about a periphery of the channel feature 1070. In some embodiments, the depth of the channel feature 1070 can range from 0.5 inches to 0.75 inches. In an exemplary embodiment, the depth of the channel feature 1070 is 0.625 inches. In other words, if the air duct 1 is nominally 10 inches in diameter, the diameter may expand to 11.25 inches in the region of the channel feature 1070.

[0055] A gasket 1048 is associated with the exterior wall 5 and is located generally over the apertures 1022. In some embodiments, one or more gasket guarding rings (not shown) may be used and fitted over the gaskets 1042, 1048. The gasket 1048 has a recessed area 1049 such that when associated with the exterior wall 5 a chamber 1049 is formed. Air flowing through the duct 1 flows over the channel feature 1070 and can enter the apertures 1022. The air can then travel through the chamber 1049 into the nipple 1028. Similar to the pressure measurement process described above with reference to FIGS. 16-23, after passing through the nipple 1028, the air can travel through a tube and into a pressure sensor for the purpose of controlling an air damper assembly.

[0056] As used in the specification and the appended claims, the singular forms "a," "an" and "the" include plural referents unless the context clearly dictates otherwise.

[0057] "Optional" or "optionally" means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where said event or circumstances occurs and instances where it does not.

[0058] Throughout the description and claims of this specification, the word "comprise" and variations of the word, such as "comprising" and "comprises," means "including but not limited to," and is not intended to exclude, for example, other additives, components, integers or steps. "Exemplary" means "an example of" and is not intended to convey an indication of a preferred or ideal embodiment. "Such as" is not used in a restrictive sense, but for explanatory purposes.

Claims

1. A damper plate for use in an air damper assembly (10, 300, 400, 500, 600) for an air duct (1), the air duct (1) having an interior wall (4) and an exterior wall (5), the air damper assembly (10, 300, 400, 500, 600) comprising an axle assembly (70) coupled to the damper plate and configured to cause the damper plate to rotate within the air duct (1) between a fully open position and a fully closed position to increase or decrease a flow of fluid through the air duct (1), the damper plate comprising: - a periphery having a straight portion (22) and a curved portion (24); and - a plurality of teeth (30, 50, 302, 303, 402, 602) spaced at least partially around and extending from the curved portion (24) of the periphery of the damper plate (12, 14), the plurality of teeth (30, 50, 302, 303, 402, 602) having a length smaller proximate to the straight portion (22) and increasing in length proximate to a midpoint of the curved portion (24), wherein the varying length provides greater control and resolution of the flow.

2. An air damper assembly (10, 300, 400, 500, 600) for an air duct (1), the air duct (1) having an interior wall (4) and an exterior wall (5), the air damper assembly (10, 300, 400, 500, 600) comprising: - the damper plate according to claim 1, wherein the plurality teeth (30, 50, 302, 303 402, 602) provide a plurality of airspaces between adjacent pairs of the plurality of teeth (30, 50, 302, 402, 602) at least partially around the periphery; and - an axle assembly (70) coupled to the damper plate and rotatably coupled to the air duct (1) such that rotation of the axle assembly (70) causes the damper plate to rotate within the air duct (1) between a fully open position and a fully closed position to control a flow of fluid through the air duct (1), wherein between the fully closed position and a partially closed position, a size of one of the plurality of airspaces varies to control a portion of the flow of fluid through the air duct (1).

3. The air damper assembly (10, 300, 400, 500, 600) of claim 2, wherein the damper plate comprises: - a first airfoil member (18, 20) having the plurality of teeth (30) made of a first material; - a second airfoil member (42, 44) having a second plurality of teeth (50) made of second material, the second material having a greater stiffness than the first material; and - at least one of: - at least a portion of the second airfoil member (42, 44) extends over at least a portion of the first airfoil member (18, 20); or - at least a portion of the first airfoil member (18, 20) extends over at least a portion of the second airfoil member (42, 44).

4. The air damper assembly (10, 300, 400, 500, 600) of claim 2 or 3, wherein at least a portion of the plurality of teeth (30, 50, 302, 303, 402, 602) are configured to contact the interior wall (4) of the air duct (1) when the damper plate is in the fully closed position; or wherein at least a portion of the plurality of teeth (30, 50, 302, 303, 402, 602) are configured to contact the interior wall (4) of the air duct (1) when the damper plate is in the partially closed position.

5. The air damper assembly (10, 300, 400, 500, 600) of one of claims 2 to 4, wherein at least a portion of the plurality of teeth (30, 50, 302, 303, 402, 602) are fabricated from polytetrafluoroethylene (Teflon).

6. The air damper assembly (10, 300, 400, 500, 600) of one of claims 2 to 4, wherein at least a portion of the plurality of teeth (30, 50, 302, 303, 402, 602) are fabricated from a metal having a plastic coating.

7. The air damper assembly (10, 300, 400, 500, 600) of one of claims 2 to 6, further comprising: - a first damper plate (12); and - a second damper plate (14) coupled to the first damper plate (12), wherein first and second airfoil members comprising sections (18, 20, 42, 44) are sandwiched between the first and second damper plates (12, 14).

8. The air damper assembly (10, 300, 400, 500, 600) of one of claims 2 to 7, further comprising a damper control assembly (100) configured to drive rotation of the axle assembly (70), wherein the damper control assembly (100) preferably comprises a pressure sensor (112), a motor (106), and an actuator (108).

9. A method of controlling a flow of fluid through an air duct (1), comprising: - receiving a target airflow setpoint; - receiving an airflow measurement from a pressure sensor (112); - generating a command to rotate a damper plate according to claim 1 to a position setpoint between a fully open position and a fully closed position based at least in part on the target airflow setpoint and the airflow measurement; and - driving the damper plate to the position setpoint.

10. The method of claim 9, wherein at least a portion of the plurality of teeth (30, 50, 302, 303, 402, 602) are configured to contact an interior wall (4) of the air duct (1) when the damper plate is in the fully closed position.

11. The method of claim 9, wherein at least a portion of the plurality of teeth (30, 50, 302, 303, 402, 602) are configured to contact an interior wall (4) of the air duct (1) when the damper plate is in a partially closed position.

12. The method of one of claims 9 to 11, wherein the damper plate comprises: - a first airfoil member (18, 20) having the plurality of teeth (30) made of a first material; - a second airfoil member (42, 44) having a second plurality of teeth (50) made of second material, the second material having a greater stiffness than the first material.

13. A method of providing an air damper assembly (10, 300, 400, 500, 600) for an air duct (1), the air duct (1) having an interior wall (4) and an exterior wall (5), comprising: - providing a damper plate according to claim 1; and - providing an axle assembly (70) fixedly coupled to the damper plate (12, 14) and rotatably coupled to the air duct (1) such that rotation of the axle assembly (70) causes the damper plate (12, 14) to rotate within the air duct (1) and increase or decrease fluid flow therethrough.

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