The present disclosure relates, in exemplary embodiments, to air duct dampers. More particularly, exemplary embodiments relate to air dampers with controllable resolution at lower flow rates.
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.
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.
One implementation of the present disclosure is an air damper assembly for an air duct having an interior wall and an exterior wall. 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.
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.
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.
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.
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.
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.
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.
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.
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.
Another implementation of the present disclosure is a method for controlling a flow of fluid through an air duct. The method includes receiving a target airflow setpoint, receiving an airflow measurement from a pressure sensor, and generating a command to rotate a damper plate 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. The damper plate has 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 method further includes driving the damper plate to the position setpoint.
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.
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.
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.
Yet another implementation of the present disclosure is a method of providing an air damper assembly for an air duct having an interior wall and an exterior wall. The method includes providing an air damper assembly that 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 method further includes providing 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.
The drawings disclose exemplary embodiments in which like reference characters designate the same or similar parts throughout the figures of which:
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.
Referring now to
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.
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
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.
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).
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.
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.
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 100. In various embodiments, the optional gasket can be fabricated from rubber, silicone, neoprene, a plastic polymer, or any other suitable gasket material.
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
Referring now to
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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.
Referring now to
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.
Referring now to
In another alternative embodiment, the damper can have more than two rows of fingers. In one such embodiment, depicted in
Referring now to
The above description of exemplary embodiments of a damper may be for use in an air duct. It is to be understood that the damper of the present disclosure can also be used with a duct constructed for conveyance of other fluids, such as, but not limited to, gases and liquids.
The present invention also relates to a damping system comprising a duct, a damper according to the damper embodiments disclosed hereinabove and mounted in the duct, and a control assembly adapted to rotate the damper from an open to a closed position.
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.
“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.
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.
Disclosed are components that can be used to perform the disclosed methods, equipment and systems. These and other components are disclosed herein, and it is understood that when combinations, subsets, interactions, groups, etc., of these components are disclosed that while specific reference of each various individual and collective combinations and permutation of these may not be explicitly disclosed, each is specifically contemplated and described herein, for all methods, equipment and systems. This applies to all aspects of this application including, but not limited to, steps in disclosed methods. Thus, if there are a variety of additional steps that can be performed it is understood that each of these additional steps can be performed with any specific embodiment or combination of embodiments of the disclosed methods.
It should further be noted that any patents, applications and publications referred to herein are incorporated by reference in their entirety.
This application claims the benefit of and priority to U.S. Provisional Patent Application No. 62/618,206 filed Jan. 17, 2018, the entire disclosure of which is incorporated by reference herein.
Number | Date | Country | |
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62618206 | Jan 2018 | US |