Flexible filter cage for a make-up air module

A flexible filter cage for receiving an air filter in an air conditioner unit includes a first frame portion and a second frame portion spaced apart from the first frame portion to define a frame cavity therebetween. A flexible bridge extends between and flexibly connects the first frame portion and the second frame portion to permit flexing of the filter cage up to a predetermined angle which facilitates easy mounting into a filter slot defined by the air conditioner unit.

FIELD OF THE INVENTION

The present disclosure relates generally to air conditioner units, and more particularly to filter assemblies and filter cages for make-up air modules in packaged terminal air conditioner units.

BACKGROUND OF THE INVENTION

Air conditioner or conditioning units are conventionally utilized to adjust the temperature indoors—i.e. within structures such as dwellings and office buildings. Such units commonly include a closed refrigeration loop to heat or cool the indoor air. Typically, the indoor air is recirculated while being heated or cooled. A variety of sizes and configurations are available for such air conditioner units. For example, some units may have one portion installed within the indoors that is connected, by e.g., tubing carrying the refrigerant, to another portion located outdoors. These types of units are typically used for conditioning the air in larger spaces.

Another type of unit, sometimes referred to as a packaged terminal air conditioner unit (PTAC), may be used for somewhat smaller indoor spaces that are to be air conditioned. These units may include both an indoor portion and an outdoor portion separated by a bulkhead and may be installed in windows or positioned within an opening of an exterior wall of a building. PTACs often need to draw air from the outdoor portion into the indoor portion. Accordingly, certain PTACs allow for the introduction of make-up air into the indoor space, e.g., through a vent aperture defined in the bulkhead that separates the indoor and outdoor side of the unit. The vent aperture is usually equipped with an auxiliary fan and/or make-up air module to urge a flow of make-up air from the outdoor side of the PTAC into the conditioned room.

Notably, it is frequently desirable to filter the flow of make-up air entering the room through the vent aperture. However, conventional air filters are typically located in difficult to reach locations or areas with very poor accessibility and clearance, resulting in a constrained operating area and difficult installation of the filter housing and air filter. For example, for certain conventional PTACs, a rigid filter housing may be screwed or otherwise fixed or mechanically fastened to a front faceplate of the makeup air module, e.g., on an outdoor facing portion of the unit. Properly positioning the filter housing, installing the mechanical fasteners, and replacing air filters in these units may be a very difficult and time-consuming process.

Accordingly, improved air conditioner units having improved filter assemblies would be useful. More specifically, a filter cage or housing that facilities quick and easy replacement of an air filter in a packaged terminal air conditioner unit would be particularly beneficial.

BRIEF DESCRIPTION OF THE INVENTION

In accordance with one embodiment, a packaged terminal air conditioner unit defining a vertical direction, a lateral direction, and a transverse direction is provided. The packaged terminal air conditioner unit includes a bulkhead defining an indoor portion and an outdoor portion, a vent aperture defined in the bulkhead, and an auxiliary fan positioned proximate the vent aperture and being configured for urging a flow of make-up air from the outdoor portion through the vent aperture to the indoor portion. A filter cage is positioned adjacent the auxiliary fan and is configured for receiving an air filter. The filter cage includes a first frame portion, a second frame portion spaced apart from the first frame portion to define a frame cavity therebetween, and a flexible bridge extending between and flexibly connecting the first frame portion and the second frame portion.

In accordance with another embodiment, a filter assembly for a make-up air module is provided. The filter assembly includes a filter cage including a first frame portion, a second frame portion spaced apart from the first frame portion to define a frame cavity therebetween, and a flexible bridge extending between and flexibly connecting the first frame portion and the second frame portion. An air filter is positionable within the filter cavity for filtering a flow of make-up air passing through the make-up air module.

DETAILED DESCRIPTION OF THE INVENTION

As used herein, the terms “first,” “second,” and “third” may be used interchangeably to distinguish one component from another and are not intended to signify location or importance of the individual components. The terms “upstream” and “downstream” refer to the relative direction with respect to fluid flow in a fluid pathway. For example, “upstream” refers to the direction from which the fluid flows and “downstream” refers to the direction to which the fluid flows. In addition, terms of approximation, such as “approximately,” “substantially,” or “about,” refer to being within a ten percent margin of error.

Referring now toFIG. 1, an air conditioner unit10is provided. The air conditioner unit10is a one-unit type air conditioner, also conventionally referred to as a room air conditioner or a packaged terminal air conditioner (PTAC). The unit10includes an indoor portion12and an outdoor portion14, and generally defines a vertical direction V, a lateral direction L, and a transverse direction T. Each direction V, L, T is perpendicular to each other, such that an orthogonal coordinate system is generally defined.

A housing20of the unit10may contain various other components of the unit10. Housing20may include, for example, a rear grill22and a room front24which may be spaced apart along the transverse direction T by a wall sleeve26. The rear grill22may be part of the outdoor portion14, and the room front24may be part of the indoor portion12. Components of the outdoor portion14, such as an outdoor heat exchanger30, an outdoor fan32(FIG. 2), and a compressor34(FIG. 2) may be housed within the wall sleeve26. A casing36may additionally enclose outdoor fan32, as shown.

Referring now also toFIG. 2, indoor portion12may include, for example, an indoor heat exchanger40(FIG. 1), a blower fan or indoor fan42, and a heating unit44. These components may, for example, be housed behind the room front24. Additionally, a bulkhead46may generally support and/or house various other components or portions thereof of the indoor portion12, such as indoor fan42and the heating unit44. Bulkhead46may generally separate and define the indoor portion12and outdoor portion14.

Outdoor and indoor heat exchangers30,40may be components of a refrigeration loop48, which is shown schematically inFIG. 3. Refrigeration loop48may, for example, further include compressor34and an expansion device50. As illustrated, compressor34and expansion device50may be in fluid communication with outdoor heat exchanger30and indoor heat exchanger40to flow refrigerant therethrough as is generally understood. More particularly, refrigeration loop48may include various lines for flowing refrigerant between the various components of refrigeration loop48, thus providing the fluid communication there between. Refrigerant may thus flow through such lines from indoor heat exchanger40to compressor34, from compressor34to outdoor heat exchanger30, from outdoor heat exchanger30to expansion device50, and from expansion device50to indoor heat exchanger40. The refrigerant may generally undergo phase changes associated with a refrigeration cycle as it flows to and through these various components, as is generally understood. Suitable refrigerants for use in refrigeration loop48may include pentafluoroethane, difluoromethane, or a mixture such as R410a, although it should be understood that the present disclosure is not limited to such example and rather that any suitable refrigerant may be utilized.

As is understood in the art, refrigeration loop48may be alternately be operated as a refrigeration assembly (and thus perform a refrigeration cycle) or a heat pump (and thus perform a heat pump cycle). As shown inFIG. 3, when refrigeration loop48is operating in a cooling mode and thus performs a refrigeration cycle, the indoor heat exchanger40acts as an evaporator and the outdoor heat exchanger30acts as a condenser. Alternatively, when the assembly is operating in a heating mode and thus performs a heat pump cycle, the indoor heat exchanger40acts as a condenser and the outdoor heat exchanger30acts as an evaporator. The outdoor and indoor heat exchangers30,40may each include coils through which a refrigerant may flow for heat exchange purposes, as is generally understood.

According to an example embodiment, compressor34may be a variable speed compressor. In this regard, compressor34may be operated at various speeds depending on the current air conditioning needs of the room and the demand from refrigeration loop48. For example, according to an exemplary embodiment, compressor34may be configured to operate at any speed between a minimum speed, e.g., 1500 revolutions per minute (RPM), to a maximum rated speed, e.g., 3500 RPM. Notably, use of variable speed compressor34enables efficient operation of refrigeration loop48(and thus air conditioner unit10), minimizes unnecessary noise when compressor34does not need to operate at full speed, and ensures a comfortable environment within the room.

In exemplary embodiments as illustrated, expansion device50may be disposed in the outdoor portion14between the indoor heat exchanger40and the outdoor heat exchanger30. According to the exemplary embodiment, expansion device50may be an electronic expansion valve that enables controlled expansion of refrigerant, as is known in the art. More specifically, electronic expansion device50may be configured to precisely control the expansion of the refrigerant to maintain, for example, a desired temperature differential of the refrigerant across the indoor heat exchanger40. In other words, electronic expansion device50throttles the flow of refrigerant based on the reaction of the temperature differential across indoor heat exchanger40or the amount of superheat temperature differential, thereby ensuring that the refrigerant is in the gaseous state entering compressor34. According to alternative embodiments, expansion device50may be a capillary tube or another suitable expansion device configured for use in a thermodynamic cycle.

According to the illustrated exemplary embodiment, outdoor fan32is an axial fan and indoor fan42is a centrifugal fan. However, it should be appreciated that according to alternative embodiments, outdoor fan32and indoor fan42may be any suitable fan type. In addition, according to an exemplary embodiment, outdoor fan32and indoor fan42are variable speed fans. For example, outdoor fan32and indoor fan42may rotate at different rotational speeds, thereby generating different air flow rates. It may be desirable to operate fans32,42at less than their maximum rated speed to ensure safe and proper operation of refrigeration loop48at less than its maximum rated speed, e.g., to reduce noise when full speed operation is not needed. In addition, according to alternative embodiments, fans32,42may be operated to urge make-up air into the room.

According to the illustrated embodiment, indoor fan42may operate as an evaporator fan in refrigeration loop48to encourage the flow of air through indoor heat exchanger40. Accordingly, indoor fan42may be positioned downstream of indoor heat exchanger40along the flow direction of indoor air and downstream of heating unit44. Alternatively, indoor fan42may be positioned upstream of indoor heat exchanger40along the flow direction of indoor air, and may operate to push air through indoor heat exchanger40.

Heating unit44in exemplary embodiments includes one or more heater banks60. Each heater bank60may be operated as desired to produce heat. In some embodiments as shown, three heater banks60may be utilized. Alternatively, however, any suitable number of heater banks60may be utilized. Each heater bank60may further include at least one heater coil or coil pass62, such as in exemplary embodiments two heater coils or coil passes62. Alternatively, other suitable heating elements may be utilized.

The operation of air conditioner unit10including compressor34(and thus refrigeration loop48generally) indoor fan42, outdoor fan32, heating unit44, expansion device50, and other components of refrigeration loop48may be controlled by a processing device such as a controller64. Controller64may be in communication (via for example a suitable wired or wireless connection) to such components of the air conditioner unit10. According to exemplary embodiments, controller64may include a memory and one or more processing devices such as microprocessors, CPUs or the like, such as general or special purpose microprocessors operable to execute programming instructions or micro-control code associated with operation of unit10. The memory may represent random access memory such as DRAM, or read only memory such as ROM or FLASH. In one embodiment, the processor executes programming instructions stored in memory. The memory may be a separate component from the processor or may be included onboard within the processor.

Unit10may additionally include a control panel66and one or more user inputs68, which may be included in control panel66. The user inputs68may be in communication with the controller64. A user of the unit10may interact with the user inputs68to operate the unit10, and user commands may be transmitted between the user inputs68and controller64to facilitate operation of the unit10based on such user commands. A display70may additionally be provided in the control panel66, and may be in communication with the controller64. Display70may, for example be a touchscreen or other text-readable display screen, or alternatively may simply be a light that can be activated and deactivated as required to provide an indication of, for example, an event or setting for the unit10.

Referring briefly toFIG. 4, a vent aperture80may be defined in bulkhead46providing fluid communication between indoor portion12and outdoor portion14. Vent aperture80may be utilized in an installed air conditioner unit10to allow outdoor air to flow into the room through the indoor portion12. In this regard, in some cases it may be desirable to allow outside air (i.e., “make-up air”) to flow into the room in order, e.g., to meet government regulations, or to compensate for negative pressure created within the room. In this manner, according to an exemplary embodiment, make-up air may be provided into the room through vent aperture80when desired.

As shown inFIG. 5, a vent door82may be pivotally mounted to the bulkhead46proximate to vent aperture80to open and close vent aperture80. More specifically, as illustrated, vent door82is pivotally mounted to the indoor facing surface of indoor portion12. Vent door82may be configured to pivot between a first, closed position where vent door82prevents air from flowing between outdoor portion14and indoor portion12, and a second, open position where vent door82is in an open position (as shown inFIG. 5) and allows make-up air to flow into the room. According to the illustrated embodiment vent door82may be pivoted between the open and closed position by an electric motor84controlled by controller64, or by any other suitable method.

In some cases, it may be desirable to treat or condition make-up air flowing through vent aperture80prior to blowing it into the room. For example, outdoor air which has a relatively high humidity level may require treating before passing into the room. In addition, if the outdoor air is cool, it may be desirable to heat the air before blowing it into the room. Therefore, as illustrated inFIG. 6, unit10may further include an auxiliary sealed system, or make-up air module90, for conditioning make-up air. As shown, make-up air module90and/or an auxiliary fan92are positioned within outdoor portion14adjacent vent aperture80and vent door82is positioned within indoor portion12over vent aperture80, though other configurations are possible. According to the illustrated embodiment auxiliary sealed system90may be controlled by controller64, by another dedicated controller, or by any other suitable method.

As illustrated, make-up air module90includes auxiliary fan92that is configured as part of auxiliary sealed system90and may be configured for urging a flow of air through auxiliary sealed system90. Auxiliary sealed system90may further include one or more compressors, heat exchangers, and any other components suitable for operating auxiliary sealed system90similar to refrigeration loop48described above to condition make-up air. For example, auxiliary system90can be operated in a dehumidification mode, an air conditioning mode, a heating mode, a fan only mode where only auxiliary fan92is operated to supply outdoor air, an idle mode, etc.

Referring now generally toFIGS. 7 through 13, a filter assembly100which may be used to filter a flow of makeup air (e.g., as identified by reference numeral102inFIGS. 12 and 13) will be described according to exemplary embodiments of the present subject matter. Filter assembly100is generally designed to facilitate a quick and easy installation or replacement of an air filter104(seeFIG. 9). Although filter assembly100is described herein as being used with makeup air module90of packaged terminal air conditioner unit10, it should be appreciated that according to alternative embodiments, filter assembly100may be used for mounting an air filter on any suitable air moving device, air conditioning system, fan system, etc.

As illustrated, filter assembly100may include a receiving structure or mounting features defined on makeup air module90, auxiliary fan92, etc. Specifically, as illustrated, the fan housing110of auxiliary fan92may define a receiving slot112that is positioned upstream of auxiliary fan92. Specifically, as best shown inFIG. 7, receiving slot112may be defined by an extended portion114of fan housing110, e.g., a structure which extends upstream of and away from auxiliary fan92to a distal end. At the distal end of extended portion114, a raised lateral flange116extends toward a center of the receiving slot112, e.g., substantially along the vertical direction V. In this regard, raised lateral flange116may extend upward from a bottom, distal end of extended portion114of fan housing110. In addition, housing110may define one or more raised vertical flanges118that extend toward the center of receiving slot112along the sides of receiving slot112. In this regard, according to the illustrated embodiment, raised flanges116,118surround receiving slot112on three sides, though alternative embodiments may use more or flanges.

Filter assembly100may further include a filter cage120which is generally configured for receipt within receiving slot112. In addition, filter cage120is designed to receive air filter104for filtering the flow of makeup air102during operation of makeup air module90. Notably, as described below, filter cage120is designed and constructed to be flexible for quick and easy installation into receiving slot112of fan housing110. However, it should be appreciated that the way filter cage120is described as being received within fan housing110is only one exemplary application of the present subject matter. Variations and modifications may be made to fan housing110, filter cage120, or other components of packaged terminal air conditioner unit10while remaining within the scope of the present subject matter.

According to exemplary embodiments, filter cage120may be formed from any material which is sufficiently rigid to support air filter104during operation of packaged terminal air conditioner unit10. For example, filter cage120may be formed by injection molding, e.g., using a suitable plastic material, such as polypropylene, injection molding grade high impact polystyrene (HIPS), or acrylonitrile butadiene styrene (ABS). Alternatively, according to the exemplary embodiment, these components may be compression molded, e.g., using sheet molding compound (SMC) thermoset plastic or other thermoplastics. According still other embodiments, filter cage120may be formed from metal or any other suitable rigid material, such as sheet metal.

As shown, filter cage120generally includes a first frame portion122and a second frame portion124which are spaced apart from each other to define a frame cavity126therebetween. In this regard, according to the illustrated embodiment, first frame portion122includes an upper member130and a lower member132, which each extend substantially within a plane defined by the lateral direction L and transverse direction T. In addition, first frame portion122includes a vertical member134that extends between upper member130to lower member132, e.g., to form a substantially U-shape. Each of the members130-134of filter cage120may generally extend between an upstream or forward end136and a downstream or aft end138of filter cage120along the transverse direction T.

According to an exemplary embodiment, aft end138of filter cage120is in contact with or pressed against a forward end of auxiliary fan92housings. According to one exemplary embodiment, vertical member134may be a substantially flat member that extends within a plane defined by the vertical direction V and the transverse direction T. However, according to the illustrated embodiment, vertical member134may be angled slightly relative to the transverse direction T such that an end of air filter104may slide between vertical member134and aft end138of filter cage120to secure it in place and prevent it from falling forward out of filter cage120.

According to exemplary embodiments, second frame portion124may be substantially the same or similar to first frame portion122. Due to the similarity between first frame portion122and second frame portion124, similar reference numerals will be used to refer to the various pieces of such frame portions. In this regard, second frame portion124may similarly include an upper member130, a lower member132, and a vertical member134. According to the illustrated embodiment, second frame portion124may be slightly shorter than first frame portion122along the lateral direction L. In addition, vertical member134is illustrated as extending substantially within the plane defined along the vertical direction V and transverse direction T (e.g., instead of being angled as described above). In this manner, during installation of air filter104, the filter may slide into the tapered or angled vertical member134defined within first frame portion122and may sit flush against vertical member134of second frame portion124.

Filter cage120may define additional features for retaining air filter104after installation. For example, filter cage120may define one or more retention members140which extend from forward end138inward toward frame cavity126. In addition, each of first frame portion122and second frame portion124may define cross supports142that extend within a plane orthogonal to the transverse direction T proximate aft end138of filter cage120. For example, as illustrated, cross supports142are thin members that extend within a plane defined by the vertical direction V and lateral direction L. In addition, according to the illustrated embodiment, filter cage120may define one or more finger grip recesses144within cross supports142. In this manner, a user may squeeze cross supports142using finger grip recesses144to flex filter cage120and to facilitate easy installation into receiving slot112.

According to the illustrated embodiment, first frame portion122and second frame portion124are spaced apart along the lateral direction L by a gap146that is sufficient to permit movement between first frame portion122and second frame portion124. According to exemplary embodiments, gap146may be greater than about 0.1 millimeters, greater than about 2 millimeters, greater than about 5 millimeters, or greater than about 10 millimeters. In addition, or alternatively, gap146may be less than about 20 millimeters, less than about 15 millimeters, less than about 10 millimeters, or less than about 5 millimeters. Other sizes of gap146are possible and within the scope of the present subject matter.

As illustrated in the figures, filter cage120may further include a flexible bridge150that extends between and flexibly connects first frame portion122and second frame portion124. In general, flexible bridge150may be any mechanical connection between the first frame portion122and second frame portion124that permits flexing therebetween. For example, according to exemplary embodiments, flexible bridge150may be a mechanical hinge or joint that is positioned between first frame portion122and second frame portion124. According to still other embodiments, flexible bridge150may be a weakened or tapered portion defined between first frame portion122and second frame portion124. Other configurations are possible and within scope of the present subject matter.

As best illustrated inFIGS. 8 through 11, filter cage120may further include an elongated flange152that extends from an outer surface154of both first frame portion122and second frame portion124. In this regard, elongated flange152extends away from frame cavity126and is configured for engaging receiving slot112to secure filter cage120in place after installation. In addition, elongated flange152may provide rigidity to filter cage120at the desired locations. As shown, elongated flange152defines a nominal thickness156is sufficient for providing rigidity to filter cage120. In addition, as illustrated, flexible bridge150is a tapered portion158of elongated flange152. In this regard, tapered portion158may define a tapered thickness160which may be smaller than the nominal thickness156. Specifically, according to exemplary embodiments, tapered thickness160may be less than three quarters, less than half, less than one quarter, or less, than nominal thickness156.

Referring now specifically toFIG. 10, first frame portion122of filter cage120may define a first blocking face162and second frame portion122of filter cage120may define a second blocking face164. In general, first blocking face162and second blocking face164may be any suitable features defined on filter cage120which prevent flexing of filter cage120beyond a predetermined angle. Specifically, according to the illustrated embodiment, first blocking face162and second blocking face164to define a flex angle166when filter cage120is in the relaxed position. For example, flex angle166may be between about 2 degrees and 45 degrees, between about 5 and 30 degrees, between about 10 and 20 degrees, or about 15 degrees.

As best shown inFIG. 11, filter cage120may further include a locking rib170that is spaced apart from elongated flange152along the transverse direction T. Specifically, locking rib170is defined on a bottom of filter cage120, e.g., on an outer surface154of lower members132. Notably, locking rib170may be spaced apart from elongated flange152by a distance substantially equivalent to a thickness of raised lateral flange116. In this manner, filter cage120may be secured in place when elongated flange152and locking rib170straddle raised lateral flange116. Thus, when properly installed, raised lateral flange116is seated or squeezed between elongated flange152and locking rib170to prevent further flexing of filter cage120, thereby locking filter cage120in the relaxed position.

In this manner, filter assembly100may be simply and easily installed into receiving slot112of makeup air module90. Specifically, filter cage120may be installed by squeezing on finger grip recesses144to flex filter cage120at flexible bridge150up to flex angle166. When filter cage120is flexed in this manner, the lateral dimension or width of filter cage120is minimized such that a left end of filter cage120(e.g. vertical member134of the first frame portion122) may slide from right to left into receiving slot112. The user may then release filter cage120such that the natural resiliency of flexible bridge150springs filter cage120back into a relaxed position. In this position, an aft and138of filter cage120sits flush with a forward face of auxiliary fan92. After filter cage120is in place, air filter104may slide into filter cage120and be retained by retention members140. Notably, the entire installation process of filter assembly100may be completed without the use of tools and within the constrained space available within packaged terminal air conditioner unit100.