Backdraft Damper with Angled Frame for Terminal Unit

This application is a non-provisional of and claims the benefit of U.S. Provisional Patent Application No. 63/645,693, filed on May 10, 2024, the entire contents of which are incorporated herein by reference.

This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present techniques, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.

A heating, ventilation, and/or air conditioning (HVAC) system is often utilized to regulate environmental conditions, such as temperature and/or humidity, within a building or other conditioned space. For example, an HVAC system may include equipment, such as one or more heat exchangers deployed in an HVAC unit, which operates to produce a flow of supply air. To direct the supply air to a conditioned space, the HVAC system may include ductwork configured to direct the supply air from the HVAC unit to the conditioned space. In some applications, the HVAC system may include a terminal unit connected to an end of the ductwork. The terminal unit may discharge the supply air toward the conditioned space. Additionally, the terminal unit may be configured to receive a flow of plenum air, such as air within a plenum or space above a ceiling of the conditioned space. The terminal unit may also be desired to direct the plenum air flow to the conditioned space in order to recirculate air within the conditioned space. Unfortunately, existing terminal units are susceptible to various inefficiencies and operational inconveniences. For example, existing terminal units are susceptible to inefficient recirculation of air flow within the terminal unit.

A summary of certain examples disclosed herein is set forth below. It should be noted that these aspects are presented merely to provide the reader with a brief summary of these certain examples and that these aspects are not intended to limit the scope of this disclosure. Indeed, this disclosure may encompass a variety of aspects that may not be set forth below.

In an example, a terminal unit for a heating, ventilation, and/or air conditioning (HVAC) system, comprises a collar where the collar includes a first collar frame wall defining a first opening and a second collar frame wall defining a second opening, wherein the second opening is positioned at an angle relative to the first opening. The terminal unit also includes a damper door, rotatably attached to the collar at a pivot, configured to abut the collar at the angle relative to the first opening to substantially cover the second opening in a closed position.

In some aspects, the techniques described herein relate to a terminal unit for a heating, ventilation, and/or air conditioning (HVAC) system, including: a housing including a base wall, a first chamber configured to receive a first air flow, and a second chamber configured to receive a second air flow; an internal wall disposed within the housing and extending between the first chamber and the second chamber, wherein the internal wall includes an opening formed therein, and wherein the second air flow selectively flows through the opening from the second chamber to the first chamber along an air flow path; and a damper door rotatable relative to the internal wall and configured to substantially prevent the first air flow from flowing through the opening from the first chamber to the second chamber in a closed position, the damper door positioned at an angle relative a vertical plane that is perpendicular to the base wall.

In some aspects, the techniques described herein relate to a terminal unit for a heating, ventilation, and/or air conditioning (HVAC) system, including: a housing including a first chamber configured to receive a first air flow and a second chamber configured to receive a second air flow; an internal wall disposed within the housing and extending between the first chamber and the second chamber, wherein the internal wall includes a first opening formed therein; a damper collar including a mounting surface configured to be coupled to the internal wall, a collar wall positioned at an angle relative to the internal wall, and a second opening extending through the damper collar, the second opening in fluid communication with the first opening; and a damper door rotatably attached to the damper collar and configured to abut the collar wall to substantially cover the second opening in a closed position.

In some aspects, the techniques described herein relate to a terminal unit for a heating, ventilation, and/or air conditioning (HVAC) system, including: a housing including a base wall, a first chamber configured to receive a first air flow, and a second chamber configured to receive a second air flow; an internal wall disposed within the housing and extending between the first chamber and the second chamber, wherein the internal wall is supported by the base wall at an oblique angle, and wherein the internal wall includes an opening formed therein; and a damper door rotatable relative to the internal wall and configured to substantially cover the opening in a closed position.

One or more specific examples of the present disclosure will be described below. These described examples are only examples of the presently disclosed techniques. Additionally, in an effort to provide a concise description of these examples, all features of an actual implementation may not be described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but may nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure.

When introducing elements of various examples of the present disclosure, the articles “a,” “an,” and “the” are intended to mean that there are one or more of the elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. Additionally, it should be understood that references to “one example” or “an example” of the present disclosure are not intended to be interpreted as excluding the existence of additional examples that also incorporate the recited features.

As used herein, the terms “approximately,” “generally,” and “substantially,” and so forth, are intended to convey that the property value being described may be within a relatively small range of the property value, as those of ordinary skill would understand. For example, when a property value is described as being “approximately” equal to (or, for example, “substantially similar” to) a given value, this is intended to mean that the property value may be within +/−5%, within +/−4%, within +/−3%, within +/−2%, within +/−1%, or even closer, of the given value. Similarly, when a given feature is described as being “substantially parallel” to another feature, “generally perpendicular” to another feature, and so forth, this is intended to mean that the given feature is within +/−5%, within +/−4%, within +/−3%, within +/−2%, within +/−1%, or even closer, to having the described nature, such as being parallel to another feature, being perpendicular to another feature, and so forth. Further, it should be understood that mathematical terms, such as “planar,” “slope,” “perpendicular,” “parallel,” and so forth are intended to encompass features of surfaces or elements as understood to one of ordinary skill in the relevant art, and should not be rigidly interpreted as might be understood in the mathematical arts. For example, a “planar” surface is intended to encompass a surface that is machined, molded, or otherwise formed to be substantially flat or smooth (within related tolerances) using techniques and tools available to one of ordinary skill in the art. Similarly, a surface having a “slope” is intended to encompass a surface that is machined, molded, or otherwise formed to be oriented at an angle (e.g., incline) with respect to a point of reference using techniques and tools available to one of ordinary skill in the art.

As will be discussed in further detail below, a heating, ventilation, and/or air conditioning (HVAC) system may include a terminal unit for delivering air to a conditioned space of a structure. In general, the terminal unit may be located near or within the conditioned space, and the terminal unit may be configured to receive one or more air flows for supply to the conditioned space. For example, the terminal unit may receive a first air flow (e.g., a primary air flow, a conditioned air flow) from an HVAC unit (e.g., air handler) via ductwork extending from the HVAC unit to the terminal unit. To this end, the terminal unit may include a first air inlet configured to receive the first air flow from the ductwork. The terminal unit may also be configured to receive a second air flow (e.g., a plenum air flow, a return air flow) via a plenum air inlet of the terminal unit. For example, the second air flow may be received from a plenum space, such as a space above a ceiling of the conditioned space, in which the terminal unit is disposed.

In some examples, the terminal unit may include a first chamber configured to receive the first air flow and to discharge the first air flow from the terminal unit. The terminal unit may also include a second chamber configured to receive the second air flow. In some examples, the terminal unit may be configured to direct the second air flow from the second chamber and into the first chamber to enable discharge of the second air flow toward the conditioned space from the first chamber. In some examples, the terminal unit may be configured to receive the first air flow, receive the second air flow, and direct the second air flow from the second chamber and into the first air flow within the first chamber to generate a mixed air flow that is discharged to the conditioned space.

The first chamber and the second chamber of the terminal unit may be generally divided by an internal wall disposed within a housing of the terminal unit. To enable flow of the second air flow from the second chamber into the first chamber, the terminal unit may include a damper (e.g., backdraft damper) coupled to the internal wall. That is, the internal wall may include an opening to fluidly couple the first chamber and the second chamber, and the damper may overlap with the opening to enable control of the second air flow from the second chamber into the first chamber. In some examples, the damper may also enable control of the first air flow from the first chamber into the second chamber. In particular, the damper may be configured to block flow of the first air flow from the first chamber into the second chamber.

In some examples, the terminal unit may include a blower configured to drive flow of air through the terminal unit. For example, the blower may be disposed within the second chamber and may be configured to force the second air flow from the second chamber and into the first chamber via the opening of the internal wall. As the blower forces the second air flow toward and through the opening, the second air flow may impinge against the damper and force the damper to transition toward an open position. In some circumstances, the blower may not be operated to force the second air flow through the terminal unit. In such instances, the damper may transition toward a closed position to at least partially block the opening in the internal wall. In this way, the damper may at least partially block flow of the first air flow from the first chamber and into the second chamber via the opening.

Unfortunately, existing dampers (e.g., backdraft dampers) in terminal units may rely upon a force of the first air flow directed through the first chamber to maintain the damper in a closed position to block flow of the first air flow into the second chamber. For example, existing backdraft dampers may include one or more protrusions (e.g., flanges) that extend outwardly from of a panel (e.g., body, door) of the damper and into a flow path of the first air flow. In some existing designs, a terminal unit may include a baffle configured to direct a portion of the first air flow toward the damper to bias the damper toward a closed position against the internal wall. In this way, the protrusions and/or baffle may harness the force of the first air flow to bias the backdraft damper toward the internal wall and in a closed position. However, traditional backdraft dampers including such features may generate acoustic energy (e.g., noise) as the first air flow contacts the protrusions, and the acoustic energy may manifest as undesirable noise and/or vibrations that are emitted from the terminal unit. Further, the protrusions of traditional backdraft dampers may create undesirable air flow resistance (e.g., a pressure drop) in the first air flow, thereby adversely affecting the discharge of air from the terminal unit and into the conditioned space. In some traditional backdraft dampers for terminal units, the backdraft damper may simply rely on the force of gravity to rest in a vertical position, whereby the backdraft damper may generally occlude the opening in the internal wall. However, as a speed of the first air flow through the first chamber increases, a pressure within the first chamber may decrease (e.g., relative to a pressure within the second chamber), thereby creating a pressure differential between the first chamber and the second chamber. In such instances, the pressure differential may urge traditional backdraft dampers toward an open position that enables undesirable flow (e.g., leakage) of the first air flow into the second chamber.

It is now recognized that improved backdraft dampers and related features may enable improved flow of air flows through a terminal unit. Accordingly, present examples are directed to backdraft damper assemblies that are configured to reduce undesired and/or unintended flow of air within and/or through the terminal unit. For example, the disclosed techniques enable a reduction in flow of air from the first chamber (e.g., primary air chamber) into the second chamber (e.g., plenum air chamber). As described in further detail below, the backdraft damper assembly may include a damper collar (e.g., damper frame) and a damper door. The damper collar may be coupled to an internal wall of the terminal unit and may generally extend about (e.g., surround) an opening formed in the internal wall. The damper door may be mechanically attached to an upper portion (e.g., side, edge, frame) of the damper collar, such as via a hinge, and the damper door may be configured to rotate or pivot (e.g., via the hinge) relative to the damper collar to enable and/or block air flow through the opening of the internal wall. The damper collar may be configured to harness (e.g., utilize) a force of gravity to bias or urge the damper door toward a closed position, such as during instances in which a blower of the terminal unit is not operating to force the second air flow (e.g., plenum air flow) into the first chamber. For example, the damper collar may have an angled or slanted geometry against which the damper door may rest via the force of gravity acting on the damper door, such as during non-operation of the blower. In this way, the damper door may rest against the damper collar in a closed position under the force of gravity, which may reduce flow of the first air flow from the first chamber and into the second chamber of the primary airflow into the plenum space, and the plenum airflow into the mixing chamber. Indeed, present examples enable improper operation of backdraft dampers to control flow of air through a terminal unit without use of protrusions, baffles, and/or other features that may otherwise impede flow of the first air flow through the terminal unit and/or generate undesirable air flow recirculation, acoustic energy, noise, vibrations, and so forth.

Turning now to the drawings,illustrates an example of a heating, ventilation, and/or air conditioning (HVAC) system for environmental management that may employ one or more HVAC units. As used herein, an HVAC system includes any number of components configured to enable regulation of parameters related to climate characteristics, such as temperature, humidity, air flow, pressure, air quality, and so forth. For example, an “HVAC system” as used herein is defined as conventionally understood and as further described herein. Components or parts of an “HVAC system” may include, but are not limited to, all, some of, or individual parts such as a heat exchanger, a heater, an air flow control device, such as a fan, a sensor configured to detect a climate characteristic or operating parameter, a filter, a control device configured to regulate operation of an HVAC system component, a component configured to enable regulation of climate characteristics, or a combination thereof. An “HVAC system” is a system configured to provide such functions as heating, cooling, ventilation, dehumidification, pressurization, refrigeration, filtration, or any combination thereof. The examples described herein may be utilized in a variety of applications to control climate characteristics, such as residential, commercial, industrial, transportation, or other applications where climate control is desired.

In the illustrated example, a buildingis air conditioned by a system that includes an HVAC unit. The buildingmay be a commercial structure or a residential structure. As shown, the HVAC unitis disposed on the roof of the building. However, the HVAC unitmay be located in other equipment rooms or areas adjacent the building. The HVAC unitmay be a single packaged unit containing other equipment, such as a blower, heat exchangers, integrated air handler, and/or auxiliary heating unit. In other examples, the HVAC unitmay be part of a split HVAC system, which includes an outdoor HVAC unit and an indoor HVAC unit.

The HVAC unitmay be an air-cooled device that implements a refrigeration cycle to provide conditioned air to the building. Specifically, the HVAC unitmay include one or more heat exchangers across which an air flow is passed to condition the air flow before the air flow (e.g., primary air flow) is supplied to the building. In the illustrated example, the HVAC unitis a rooftop unit (RTU) that conditions a supply air stream, such as environmental air and/or a return air flow drawn from the building. After the HVAC unitconditions the air flow, the air flow, also referred to herein as a primary air flow, is supplied to the buildingvia ductworkextending throughout the buildingfrom the HVAC unit. For example, the ductworkmay extend to various individual floors or other sections of the building. In certain examples, the HVAC unitmay be a heat pump that provides both heating and cooling to the building with one refrigeration circuit configured to operate in different modes. In other examples, the HVAC unitmay include one or more refrigeration circuits for cooling an air flow and a furnace for heating the air flow. The primary air flow supplied to the buildingby the HVAC unitmay include environmental air, such as air from outside the building, and/or recirculated air from within the building, which may or may not be actively and/or passively heated or cooled by the HVAC unit. For example, the HVAC unitmay operate in a recirculating or economizer mode, such that the supply air flow, and thus the primary air flow, is not actively heated or cooled in some operating modes.

A control device, one type of which may be a thermostat, may be used to designate a desired temperature of a conditioned spacewithin the building. The control devicealso may be used to control the flow of air, such as volume, through the ductworkto different areas within the conditioned space. For example, the control devicemay be used to regulate operation of one or more components of the HVAC unitor other components, such as dampers, fans, and/or terminal unitswithin the buildingthat may control the flow of air through and/or from the ductwork. In some examples, other devices may be included in the system, such as pressure and/or temperature transducers or switches that sense the temperatures and pressures of the conditioned air, return air, and so forth. Moreover, the control devicemay include computer systems that are integrated with or separate from other building control or monitoring systems, including systems that are remote from the building.

As mentioned above, an HVAC system may include one or more terminal unitsfluidly coupled to the ductworkof the HVAC system. The terminal unitsmay each be configured to receive a first air flow, such as the primary air flow discharged by the HVAC unit, and may direct the first air flow into the conditioned space. In some examples, the terminal unitsmay also be configured to receive a second air flow, such as a plenum air flow or return air flow. To this end, the terminal unitsmay be disposed within and/or adjacent a plenum spacewithin the building. In some examples, the plenum spacemay facilitate transfer of return air back to the HVAC unit. For example, the plenum spacemay be above a dropped ceilingthat separates the plenum spacefrom the conditioned space. Moreover, in some examples, the terminal unitmay be implemented in the buildingwithout the dropped ceiling, and the terminal unitsmay be configured to receive a plenum air flow or other air flow from a portion of air near a ceiling or another area of the conditioned space.

is a schematic diagram of an example of a portionof the building, illustrating an example of the terminal unitimplemented within the building. As discussed above, the terminal unitmay receive a first air flow(e.g., a primary air flow), such as via the ductworkextending from the HVAC unit. Accordingly, the first air flowmay be a conditioned air flow (e.g., a heated air flow, a cooled air flow, a dehumidified air flow) that is produced by the HVAC unitor other HVAC system. The terminal unitmay also be configured to receive a second air flow, such as a plenum air flow from the plenum spacewithin the building. In the illustrated example, the terminal unitincludes a housingdefining a first air inletconfigured to receive the first air flowand a second air inletconfigured to receive the second air flow. The terminal unitmay be configured to mix the first air flowand the second air flowwithin the housingto generate a mixed air flow(e.g., discharge air flow, supply air flow) that is then supplied to the conditioned spacevia an air outletof the terminal unit(e.g., the housing). In some implementations, the plenum spacemay receive a return air flow, for example, drawn into the plenum spacevia a vent, which may be formed in the dropped ceiling. In some examples, a portion of the return air flowmay be directed back to the HVAC unit(e.g., via the ductwork) for conditioning. Additionally or alternatively, a portion of the return air flowmay be drawn into the housingof the terminal unit, via the second air inlet, as the second air flow. The mixed air flowmay include a portion of the first air flowand/or a portion of the second air flowreceived by the terminal unit. That is, during some operations of the terminal unit, the mixed air flowmay include both the first air flowand the second air flow, and in other operations the mixed air flowmay include one of the first air flowor the second air flowwithout the other of the first air flowor the second air flow. To this end, the terminal unitmay include one or more valves, dampers, and/or other flow control device configured to regulate flow of air (e.g., first air flow, the second air flow) into and/or through the housing. For example, if the first air inletof the terminal unitor the second air inletof the terminal unitis closed (e.g., via a damper or valve), the mixed air flowmay include air from a single source. In other words, if the first air inletis closed, the terminal unitmay receive and supply the second air flowalone to the conditioned space, and if the second air inletis closed, the terminal unitmay receive and supply the first air flowalone to the conditioned space

As mentioned above, present examples are directed to systems and methods configured to enable improved control of air flow through the terminal unit. In particular, examples of the terminal unitincorporating the present techniques may include a damper assembly(e.g., backdraft damper assembly) configured to block undesired flow of air through the terminal unit. For example, the damper assemblymay be configured to block a flow (e.g., a backdraft) of the first air flowthrough the terminal unit, such as toward the second air inlet. In this way, the present techniques may enable more efficient operation of the terminal unitand/or the HVAC unit. For example, one or more fans or blowers of the terminal unitand/or the HVAC unitmay be operated with reduced energy consumption due to more efficient flow of air through the terminal unit. Details of the damper assemblyare described further below.

is a perspective view of a portion of an example of the terminal unitincluding the damper assemblyand the control system. As mentioned above, the terminal unitincludes the housinghaving a first end wall, a second end wallopposite the first end wall, a first side wall, a second side wallopposite the first side wall, a base wallcoupled to each of the walls-, and a top wall (not shown) coupled to each of the walls-and opposite the base wall. In the illustrated example, the first air inletis positioned in the first end walland configured to receive the first air flow. In the illustrated example, the second air inletis positioned in the first end walland configured to receive the second air flow. In the illustrated example, the air outletis positioned in the second end walland configured to discharge the first air flowand/or the second air flowreceived by the terminal unit. In other examples, the first inlet, the second inlet, and the air outletmay be positioned in other walls of the housing. Another example of the relative positions of the inlets,and the outletis discussed below with respect to. The housinggenerally defines a first chamber(e.g., first section, first volume) configured to receive the first air flowvia the first air inletand a second chamber(e.g., second section, second volume) configured to receive the second air flowvia the second air inlet. In the illustrated example, the first chambergenerally extends from the first air inletto the air outletdefined by the housing. In some examples, the terminal unitmay include an inlet valveconfigured to enable flow of the first air flowfrom the HVAC unitto the terminal unit. The second air inletmay be an opening formed in the housingand may be exposed to the plenum spacewithin the buildingto enable flow of the second air flowfrom the plenum spaceinto the terminal unit(e.g., the second chamber).

The first chamberand the second chamberwithin the housingare generally divided (e.g., separated) by an internal walldisposed within the housing. As shown, the internal wallis supported by and coupled to the base wall. The internal wallextends between the first and second end walls,. In the illustrated example, the internal wallis positioned at a substantially perpendicular angle relative to the base wall. As described in further detail below with reference to, the internal wallincludes an openingconfigured to enable fluid coupling of the first chamberand the second chamber. In accordance with present techniques, the terminal unitincludes the damper assembly(e.g., backdraft damper assembly) configured to enable improved control of air flow through the openingand between the first chamberand the second chamber. The damper assemblyis configured to couple to the internal wall, such that the damper assemblygenerally overlaps with the openingformed in the internal wall. In the illustrated example, the damper assemblyis coupled to the internal walland is disposed within the first chamber.

As described in further detail below, the damper assemblyofmay include a damper collar(e.g., damper frame, damper mount) that is attached (e.g., fixed) to the internal walland generally surrounds the openingformed in the internal wall. As shown, the damper collarthus defines an openingextending therethrough that is configured to be in fluid communication with the openingin the internal wall. The damper collarmay include a mounting flangeconfigured to mount the damper collarto the internal wallof the terminal unit. The mounting flangemay include mounting holes configured to receive fasteners, screws, or any other suitable attachment device to secure the damper collarto the internal wall. Further, in other examples, the damper collarmay be affixed to the internal wallof the terminal unitvia welding, adhesives, or any other suitable attachment mechanism. The damper assemblymay also include a damper door(e.g., panel, cover) adjustably coupled to the damper collar. For example, the damper doormay be coupled to damper collarvia a hinge, a pivot joint, or other suitable connection configured to enable relative movement between the damper collarand the damper door. In the illustrated example, the damper dooris shown in a closed position, whereby the damper dooroverlaps with the openings,formed in the damper collarand the internal wallto block air flow between the first chamberand the second chamber.

As will be appreciated, it may be desirable to enable flow of the second air flow(e.g., received via the second air inlet) from the second chamberto the first chamberto enable discharge of the second air flowfrom the terminal unitvia the air outlet. To this end, the terminal unitmay include a blowerdisposed within the second chamber. The blowermay operate to draw the second air flowinto the second chambervia the second air inletand may force the second air flowto flow toward the opening formed in the internal wall. In this way, the second air flowmay be directed into the first chamberand may be discharged via the air outlet. The second air flowdriven by the blowermay impinge against the damper doorand force the damper doorto rotate or pivot at least partially into the first chamber. The second air flowmay then be directed into the first chambervia the openings,formed in the damper collarand the internal wall.

As discussed in further detail below, the damper collarmay have a configuration to enable more reliable control of air flow through the terminal unit. In particular, the damper collarmay be configured to establish an improved sealing interface between the damper collarand the damper doorin a closed position of the damper door. In some examples, the damper collarmay have an angled (e.g., inclined) configuration or geometry that enables the damper assemblyto harness a force of gravity and bias or urge the damper dooragainst the damper collarin a closed position of the damper door. That is, via force of gravity, the damper doormay rest against the damper collarto more completely seal (e.g., close, block) the openings,formed in the damper collarand the internal walland thereby more effectively block undesired flow of air between the first chamberand the second chamberduring certain operations of the terminal unit. For example, during instances in which the bloweris not operating (e.g., when the terminal unitreceives and discharges the first air flowand not the second air flow), the damper doormay rotate toward (e.g., via force of gravity) the damper collar. In accordance with present techniques, the damper collarmay include an angled (e.g., inclined, non-vertical) wall or surface configured to engage with the damper doorunder the force of gravity. In this way, the damper doormay more reliably rest in a closed position against the damper collarand create a sealing interface between the damper collarand the damper door, thereby enabling improved blockage of air flow between the first chamberand the second chamber. Moreover, with the damper doorabutting the damper collarunder the force of gravity, the damper doormay be more restricted from movement (e.g., relative to the damper collar) that may otherwise be induced, such as via a pressure differential between the first chamberand the second chamber). As a result, undesired flow of the first air flowfrom the first chamberto the second chamber(e.g., backflow of the first air flow) and/or undesired flow of the second air flowinto the first chambermay be reduced, which may enable more efficient operation of the terminal unit. For example, a fan or blower of an HVAC unit (e.g., HVAC unit) associated with the terminal unitmay be operated with reduced energy usage due to more efficient flow of the first air flowthrough the terminal unit.

is an exploded perspective view of an example of the damper assemblyand the internal wallof the terminal unit. As mentioned above, the internal wallis configured to extend between the first chamberand the second chamberwithin the housingof the terminal unit, and the internal wallincludes an opening(e.g., aperture) configured to enable flow of air along an air flow path (e.g., a plenum air flow path) between the first chamberand the second chamber. In accordance with present techniques, the terminal unitincludes the damper assemblyto enable improved control of air flow between the first chamberand the second chambervia the opening. More specifically, the damper assemblyis configured to enable improved regulation of flow of the second air flowfrom the second chamberinto the first chamberand to more effectively block flow of the first air flowfrom the first chamberinto the second chamber(e.g., backflow or backdraft of the first air flow).

As mentioned above, the damper assemblyincludes the damper collar, which is configured to be mounted to the internal wall(e.g., via the mounting flange), such that the damper collargenerally extends about (e.g., surrounds) the opening. In particular, the damper collarmay be coupled to a first sideof the internal wallfacing the first chamberwithin the housing. The damper assemblyalso includes the damper door, which is configured to adjustably couple to the damper collar. For example, the damper doormay couple to the damper collarvia a hinge joint(e.g., a pin connection, pivot joint). The hinge jointmay be disposed at an upper or top endof the damper assembly. Thus, the damper doormay be configured to pivot, rotate, or swing further into the first chamber, such as in response to a force applied to the damper doorby the second air flow(e.g., via operation of the blower). In other examples, the damper doormay be pivotably coupled to the internal wall(e.g., instead of the damper collar), as will be discussed in greater detail below with respect to. The damper doormay have any suitable mass to enable a force of the second air flowproduced by the blowerto rotate or pivot at least partially away from the damper collarand bias the damper doortoward an open position, thereby enabling flow of the second air flowfrom the second chamberinto the first chambervia the opening.

In a closed position, the damper doormay abut against the damper collarand may generally block or occlude the openings,to block air flow between the first chamberand the second chamber. In some examples, the damper doormay be manufactured with certain dimensions that overlap and/or are greater than corresponding dimensions of damper collar. For example, the damper doormay include a main body(e.g., main panel) and side flangesextending from the main body. In a closed position of the damper door, the side flangesmay overlap with and/or extend along lateral sides(e.g., side surfaces, lateral surfaces, side walls) of the damper collarto more fully occlude the openingand block air flow through the opening(e.g., via a space or gap between the damper doorand the damper collar. Moreover, when the damper dooris in the closed position against the damper collar, movement of the damper door, such as in a lateral direction (e.g., along an axis) may be restricted via the overlap between the side flangesand the lateral sides.

In some examples, the damper assemblymay include a gasket (e.g., a seal)positioned on or against the damper collar, such as along an outlet faceor surface of an outlet collar wall of the damper collarthat generally faces the damper door. The gasketmay be configured to create a seal between the damper doorand the damper collarin a closed position of the damper assembly. In this way, undesired flow of the first air flowfrom the first chamberto the second chamber, as well as undesired flow of the second air flowfrom the second chamberto the first chambermay be blocked. The gasketmay have a similar geometry as the outlet faceto enable the gasketto extend along a substantial portion and/or an entirety of the outlet face. The gasketmay be made of any suitable material, such as rubber, cork, silicone, a polymer, foam, and so forth.

In accordance with present techniques, the damper collarmay include a geometry or configuration configured to enable improved sealing between the damper collarand the damper doorin a closed position of the damper door. In particular, the outlet faceof the damper collarmay be disposed at an angle (e.g., acute angle, oblique angle) relative to the internal wall. As will be appreciated, in an assembled and/or installed configuration of the terminal unit, the internal wallmay extend in a generally vertical direction (e.g., aligned along a vertical axis). The damper collarmay be attached to the internal wall, and the outlet faceof the outlet collar wall may extend at an anglerelative to the internal wall. More specifically, a first surface of the internal wallto which the damper collaris coupled defines a vertical plane P that is perpendicular to the base wall. The outlet facemay extend at the anglerelative to the vertical plane P. In some examples, the outlet facemay extend at an anglerelative to an orientation (e.g., along the vertical axis) of one or more of the mounting flangesof the damper collar. In a closed position, the damper doormay rest against the outlet faceof the damper collar, such that the damper dooris disposed at the anglerelative to the internal walland the vertical plane P thereof. Indeed, a force of gravity acting on the damper doormay at least partially bias the damper dooragainst the outlet faceof the damper collar. In this way, the force of gravity may be harnessed by the damper assemblyand may be utilized to provide an improved sealing engagement between the damper doorand the damper collar, such as during non-operation of the blower.

is a side view of an example of the damper assemblyand the internal wallof the terminal unitin an assembled configuration. As mentioned above, the damper collarmay have a configuration that enables an improved sealing engagement between the damper collarand the damper doorin a closed position of the damper door. In particular, the outlet faceof the outlet collar wall of the damper collarmay be disposed at an anglerelative to a base surface (e.g., mounting surface) of an outlet collar wall. For example, the base surfacemay be at least partially defined by one or more mounting flangesof the damper collar. In the assembled configuration, the base surfacemay extend generally along the internal wallof the terminal unitand/or along the vertical axis. As shown, the openingof the damper collarextends therethrough. Due to the anglebetween the outlet collar wall and the internal wall, when the bloweris operating, the second air flowis guided from the second chamberto the first chamberthrough the openings,along the air flow path, at least a portion of which is oriented at an angle relative to the base wall. in the illustrated example, the angle of the air flow pathis non-parallel or oblique relative to the base wall

A magnitude of the anglemay be selected based on any suitable design parameters, such as a desired tangential gravitational force acting upon the damper door. The damper collarmay be manufactured to include the angledefined by the outlet faceand the base surfaceat a desired magnitude by, for example, adjusting a taper or geometry of the lateral sides(e.g., side surfaces, lateral surfaces) of the damper collarextending between the base surfaceand the outlet face. In some examples, a material utilized to manufacture the damper doormay be selected to achieve a desired tangential gravitational force acting upon the damper door. During operation of the terminal unit, force of gravity may act on the damper doorand, in some instances, may cause the damper doorto rest against the outlet face(e.g., angled surface). Indeed, during non-operation of the blower, the force of gravity may cause the damper doorto be at least partially biased against the outlet faceof the damper collarto establish an improved sealing interface between the damper doorand the damper collar. A magnitude of the anglemay additionally or alternatively be selected based on a desired resistance provided by the damper dooragainst the second air flow. In some examples, the anglemay be between approximately 0.5 degrees and 10 degrees (e.g., 0.5 degree, 1 degree, 2 degrees, 3 degrees, 4 degrees, 5 degrees, 6 degrees, 7 degrees, 8 degrees, 9 degrees, 10 degrees). The magnitude of the anglemay be any suitable value that enables flow of the second air flowto flow, such as via operation of the blower, from the second chamberto the first chamberwhile substantially blocking flow of air (e.g., first air flow, second air flow) through the openingduring non-operation of the blower.

As mentioned above, the damper doormay include side flanges, extending from sides of the main bodyof the damper door. The side flangesmay be configured to overlap with the lateral sidesof the damper collar. For example, the damper doormay have a width greater than a width of the damper collar. The side flangesmay extend from the main bodyin a direction toward the damper collar, such that the side flangesmay at least partially extend along and/or overlap with the lateral sidesof the damper collarin a closed configuration of the damper door. In this way, the side flangesmay further facilitate blockage of air flow (e.g., first air flow, second air flow) through the openingduring certain operations of the terminal unit.

illustrate another example form the terminal unit′ that is similar to the terminal unitof. Therefore, like structure is identified with like reference numerals and only the differences discussed herein. As an initial matter, the example ofillustrates that the second air inletcan be positioned in the second side wall. As shown in, the internal wallis positioned at an anglerelative to the base wall. The internal wallis angled toward the second chamberand away from the first chamber. That is, as shown, a first surface of the internal wallfacing the first chamberand a second surface of the internal wallfacing the second chamberare parallel to one another and are both oriented at the angle. Moreover, the second surface is closer to the base wallthan the first surface. The angleis an acute angle between the second surface and the base wall. A magnitude of the anglemay be selected based on any suitable design parameters, such as a desired tangential gravitational force acting upon the damper door.

Moreover, in the illustrate example, the damper dooris directly coupled to the internal wall(e.g., the first surface thereof) and overlaps the opening. In the illustrated example, a blower deckis coupled to the blower and makes up a portion of the internal wall. The blower deckdefines the openingof the internal wall. As shown, the damper dooris coupled to the blower deckto overlap the openingof the internal wall. In another example, a modified damper collar, similar to the damper collardiscussed above, may be coupled to the first surface of the internal wall. In such case, the outlet collar wall and the internal wallof the modified damper collarwould be parallel to one another, rather than positioned the angle. Regardless of whether the modified damper collar is used or not, in the example of, due to the anglebetween internal walland the base wall, the damper dooris positioned at the anglerelative to a vertical plane P that is perpendicular to the base wall. Accordingly, the second air flowis guided from the second chamberto the first chamberthrough the opening(and openingif the modified damper collaris included) along the air flow path, at least a portion of which is oriented at the angle relative to the base wall. A gasket(not shown in) may surround all or a portion of the perimeter of the openingto create a seal when the dooris in the closed position, as discussed above.

During operation of the terminal unit, force of gravity may act on the damper doorand, in some instances, may cause the damper doorto rest against the first surface of the angled internal wall(or the outlet faceof the modified damper collar). Indeed, during non-operation of the blower, the force of gravity may cause the damper doorto be at least partially biased against the first surface of the internal wall(or the outlet faceof the modified damper collar) to establish an improved sealing interface between the damper doorand the internal wall(or the modified damper collar). A magnitude of the anglemay additional or alternatively be selected based on a desired resistance provided by the damper dooragainst the second air flow. In some examples, the anglemay be between approximately 80 degrees and 89.5 degrees (e.g., 80 degrees, 81 degrees, 82 degrees, 83 degrees, 84 degrees, 85 degrees, 86 degrees, 87 degrees, 88 degrees, 89 degrees, 89.5 degrees). The magnitude of the anglemay be any suitable value that enables flow of the second air flowto flow, such as via operation of the blower, from the second chamberto the first chamberwhile substantially blocking flow of air (e.g., first air flow, second air flow) through the openingduring non-operation of the blower.

The specific examples described above have been shown by way of example, and it should be understood that these examples may be susceptible to various modifications and alternative forms. It should be further understood that the claims are not intended to be limited to the particular forms disclosed, but rather to cover all modifications, equivalents, and alternatives falling within the spirit and scope of this disclosure.