Patent Description:
Conventional air conditioning units usually include an indoor unit for evaporation and heat absorption and an outdoor unit for condensation and heat dissipation. Such outdoor units or condensing units include grilles positioned over each fan to prevent foreign objects from being introduced into the flow path of the fan and serve as finger protection without impeding the fan performance. The grilles present in existing outdoor units or condensing units are typically wire grilles (made of metal). While existing wire grilles are suitable for their intended purpose, it is desirable to provide an alternate composite grille or guard without impeding the operational efficiency of the system or the compliancy with the UL standards required for such part.

<CIT> discloses a fan guard composed of a plurality of extending ribs extending from a blocking plate to an outer frame, a plurality of inner ribs arranged between the extending ribs and extending from the blocking plate to the substantial center in the radial direction, and a plurality of outer ribs arranged between the extending ribs and extending from the substantial center in the radial direction to the outer frame. The number of the inner ribs is set smaller than the number of the outer ribs.

Disclosed is an integrated diffuser grille for a coil unit as defined in claim <NUM>.

The plurality of radial spokes and the plurality of partial spokes are configured to straighten an air flow as it flows across the plurality of radial spokes and the plurality of partial spokes.

Each of the plurality of radial spokes includes a radially inner portion adjacent to the hub, a radially outer portion adjacent to the stack diffuser wall, and a radially middle portion disposed between the radially inner portion and the radially outer portion.

The radially inner portion extends from <NUM>% to about <NUM>% of the radial length, the radially middle portion extends from about <NUM>% to about <NUM>% of the radial length, and the radially outer portion extends from about <NUM>% to <NUM>% of the radial length.

Optionally, the radially inner portion of at least one of the plurality of radial spokes has at least one of a spoke pitch angle that increases from about <NUM>-<NUM> degrees to about <NUM>-<NUM> degrees relative to a circumferential direction, a camber angle that decreases from about <NUM>-<NUM> degrees to about <NUM>-<NUM> degrees, and a chord that decreases from about <NUM>%-<NUM>% to about <NUM>%-<NUM>% relative to the chord at a tip section.

Optionally, the radially outer portion of at least one of the plurality of radial spokes has at least one of a spoke pitch angle that decreases from about <NUM>-<NUM> degrees to about <NUM>-<NUM> degrees relative to a circumferential direction, a camber angle that increases from about <NUM>-<NUM> degrees to about <NUM>-<NUM> degrees, and a chord that increases from about <NUM>%-<NUM>% to <NUM>% relative to the chord at a tip section.

Optionally, the radially middle portion of at least one of the plurality of radial spokes has at least one of a spoke pitch angle that increases from about <NUM>-<NUM> degrees to about <NUM>-<NUM> degrees relative to a circumferential direction, a camber angle that is constant between about <NUM>-<NUM> degrees, and a chord that decreases from about <NUM>%-<NUM>% to about <NUM>%-<NUM>% relative to the chord at a tip section.

Each of the plurality of partial spokes has an airfoil-shape and a configuration of the plurality of partial spokes is substantially identical to a configuration of the plurality of radial spokes at a same radial position.

Optionally, the hub, the stack diffuser wall, the plurality of radial spokes, the plurality of partial spokes, and the plurality of circumferential elements are integrally formed as a single unitary structure, the single unitary structure being formed from a non-metal material.

Optionally, the single unitary structure is formed from a plastic material.

Optionally, the plurality of circumferential elements have an upstream side and a downstream side, and the upstream side of the at least one circumferential element has a non-uniform contour.

Optionally, a depth increases in a direction toward the upstream side of the at least one circumferential element at a location adjacent to an interface with each of the plurality of radial spokes.

Optionally, the radial length of the plurality of partial spokes is less than or equal to about <NUM>% of the radial length of the plurality of radial spokes.

Optionally, the grille comprises a plurality of features integrally formed with the stack diffuser wall.

Optionally, the plurality of features are radially aligned with the plurality of radial spokes and the plurality of partial spokes.

Optionally, the plurality of features are arranged in groups, the groups being spaced about a periphery of the outer wall.

Optionally, the integrated diffuser grille is part of a top cover assembly of an air chiller unit of an air conditioning system.

Optionally, the top cover assembly further comprises a fan assembly, the integrated diffuser grille being positioned in overlapping arrangement with the fan assembly to restrict access to the fan assembly.

Optionally, the integrated diffuser grille is positioned downstream of the fan assembly relative to an airflow through the fan assembly.

Referring now to <FIG>, an exemplary air-cooled chiller unit <NUM> of an air conditioning system is illustrated. The air-cooled chiller unit <NUM> may include a single coil unit <NUM>, or alternatively, a plurality of coil units <NUM> arranged in a stacked configuration. With reference now to <FIG>, each coil unit <NUM> has a housing including a base or base pan <NUM> having a generally rectangular planform. However, implementations where the planform of the base pan <NUM> is another configuration, such as square, cylindrical, or another shape for example, are also envisaged.

The base pan <NUM> supports the remainder of the components of the coil unit <NUM>. As shown, a heat exchanger assembly <NUM> is arranged within the base pan <NUM>. In the illustrated arrangement the heat exchanger assembly <NUM> includes two heat exchanger coils oriented in a V or A-shape. However, a heat exchanger assembly having another shape, such as a W-shape for example, is also contemplated herein. Further, implementations where the heat exchanger assembly <NUM> wraps about one, two, three, or four sides and/or one or more corners of the footprint of the base pan <NUM> between two headers are also possible. However, in this case, the planform of the heat exchanger assembly <NUM> need not match the planform of the base pan <NUM>. A compressor <NUM>, fluidly coupled to the heat exchanger <NUM>, is positioned within the interior of the heat exchanger <NUM> and is configured to pump refrigerant through a vapor compression cycle.

The base pan <NUM> forms a lower portion of the housing, and a top cover assembly <NUM> forms an upper portion of the housing. Along the lateral perimeter, the housing may include one or more louvered panels <NUM>, corner posts (not shown), or another structural member to connect the base pan <NUM> and the top cover assembly <NUM>. The top cover assembly <NUM> includes at least one fan assembly <NUM> and a grille or fan guard <NUM> associated with each fan assembly <NUM>. It will be appreciated that the grilles or fan guards <NUM> illustrated in <FIG>, <FIG> are of the configuration commonly used today (i.e., wire grilles made of metal). Although two fan assemblies <NUM> are shown in the drawings, it should be understood that a coil unit having a single fan assembly, or more than two fan assemblies are contemplated herein. Each fan assembly <NUM> is configured to draw ambient air radially inward and across the heat exchanger assembly <NUM>. The heated air downstream from the heat exchanger assembly <NUM> is then drawn axially across the one or more fan assemblies <NUM> and discharged upwardly through the openings in the fan guard <NUM>, to be described in more detail below. Although a coil unit <NUM> having a specific configuration is illustrated and described herein, it should be understood that a coil unit <NUM> having another configuration is also within the scope of the disclosure.

With reference now to <FIG>, an example of a top cover assembly <NUM> is illustrated in more detail. As shown, a fan assembly <NUM> of the top cover assembly <NUM> includes a housing <NUM> and a fan rotor or impeller <NUM> located within the housing <NUM>. The fan rotor <NUM> generally includes a plurality of fan blades <NUM> extending radially outward from a hub <NUM>. The distal ends <NUM> of the fan blades <NUM> may be connected to a shroud, or alternatively, the distal ends <NUM> of the fan blades <NUM> may define an orifice or throat (not shown) between the fan blades <NUM> and an adjacent surface of the housing <NUM>. A motor <NUM> operably coupled to the fan assembly <NUM>, such as via a shaft or another coupling means, such as a belt, rope, or chain for example, may be used to operate the fan assembly <NUM> by rotating the fan rotor <NUM> about a fan axis X (see <FIG>). The motor <NUM> may be oriented generally vertically, such that an axis of rotation (not shown) of the motor <NUM> is arranged parallel to or coaxial with the fan axis X. However, it should be understood that a fan assembly <NUM> having another configuration, or another type of fans, such as a mixed flow fan for example, are within the scope of the present disclosure.

With reference now to <FIG>, an integrated diffuser grille <NUM> (i.e., to replace the traditional wire grille used today, shown in <FIG>, <FIG>) is illustrated. It will be appreciated that the integrated diffuser grille <NUM> may be referred to herein as a grille <NUM>. As shown in <FIG>, the grille <NUM> includes a hub <NUM>, a stack diffuser wall or outer wall <NUM>, and a plurality of spokes <NUM> extending radially between and connected to an exterior of the hub <NUM> and an interior of the stack diffuser wall <NUM>. The stack diffuser wall <NUM> may be able to be positioned in overlapping arrangement with the housing <NUM> of the fan assembly <NUM> (shown in <FIG>), such as an exterior surface thereof for example. In this implementation the grille <NUM> includes sixteen radial spokes <NUM> spaced equidistantly about the periphery of the hub <NUM>. However, it should be understood that any number of spokes <NUM> and/or arrangements where the spokes <NUM> are non-uniformly spaced are also contemplated herein. Further, the plurality of spokes <NUM> may be substantially identical, or alternatively, a configuration of the spokes <NUM> may vary about the periphery of the hub <NUM>.

As best shown in <FIG>, a cross-section of each of the spokes <NUM> when taken in a plane oriented generally parallel to the fan axis X has an airfoil-shape. The term "airfoil shape" as known in the art and used herein refers to a shape having a generally curved leading edge, a curved or pointed trailing edge, and a curved upper and lower surface extending between and connecting the leading edge and the trailing edge. The spokes <NUM> may have a leading edge facing the upstream fan assembly <NUM> and a downstream edge facing outwardly towards the ambient atmosphere surrounding the grille <NUM>. A mid-chord point is defined at a center of an imaginary straight line extending between the leading edge and the trailing edge (also known as a chord). A stacking line of each spoke <NUM> is defined by the mid-chord point of the airfoil shaped cross-section taken over the radial span of the spoke <NUM>. The stacking line of at least one of the plurality of spokes <NUM> is substantially straight.

Where the fan assembly <NUM> is configured as an axial flow fan, the airflow A moving through the fan assembly <NUM> towards the grille <NUM> generally has both an axial component, a radial component, and a tangential component. Optionally, the plurality of spokes <NUM> are configured as outlet guide vanes. Accordingly, the configuration of the radial spokes <NUM> may be selected to straighten the flow exiting from the fan assembly <NUM>, thereby transforming swirl kinetic energy in the airflow A into static pressure rises across the spokes <NUM>. In this case, the spokes <NUM> may include lean or sweep in the circumferential or axial directions. Parameters of the spokes <NUM> that may be controlled to diffuse or straighten the air flow A include, but are not limited to spoke pitch angle, chamber angle, and chord.

The configuration of each spoke <NUM> may vary over the radial length or span of the spoke <NUM> to compensate for the conditions of the airflow A in that region. For example, each spoke <NUM> may include a radially inner portion extending from the hub (<NUM>%) to about <NUM>% of the span, a radially middle portion extending between about <NUM>% of the span and about <NUM>% of the span, and a radially outer portion extending from about <NUM>% to <NUM>% of the span. An example of a cross-section of a radially inner portion of a spoke <NUM> is shown in <FIG>. The air flow A output from the fan rotor <NUM> may have a high spanwise swirl adjacent the hub <NUM>, and therefore the radially inner portion of the spokes <NUM> aligned with the fan rotor <NUM> surrounding the hub <NUM>. In this case, the spoke pitch angle of the radially inner portion of at least one of the plurality of spokes <NUM> measured relative to the circumferential direction may gradually increase by about ten degrees or more, such as from about <NUM>-<NUM> degrees to about <NUM>-<NUM> degrees for example, relative to the circumferential direction. Alternatively, or in addition, the camber angle of the radially inner portion of at least one of the plurality of spokes <NUM> may gradually decrease by at least about <NUM> degrees, such as from about <NUM>-<NUM> degrees to about <NUM>-<NUM> degrees for example. Further, the chord of the radially inner portion may gradually decrease by about <NUM>-<NUM>%, such as from about <NUM>%-<NUM>% to about <NUM>%-<NUM>% of the chord at a tip section of the spoke <NUM>. As used herein the phrase "the tip section" refers to the distal end of the spoke <NUM>, at the interface between the spoke <NUM> and the outer wall <NUM>.

The radially middle portion of at least one of the spokes <NUM>, as shown in FIG. 7C, may have one or more of a spoke pitch angle that gradually increases by about ten degrees or more, such as from about <NUM>-<NUM> degrees to about <NUM>-<NUM> degrees relative to the circumferential direction, a constant camber angle between about <NUM>-<NUM> degrees, and a decrease in chord by about <NUM>% or more, such as from about <NUM>%-<NUM>% to about <NUM>%-<NUM>% of the chord at the tip section.

The air flow A output from the fan rotor <NUM> may have a high swirl adjacent to the distal ends <NUM> of the fan blades <NUM>. To compensate for this flow, the radially outer portion of one or more of the spokes <NUM>, see <FIG>, which is axially aligned with the distal ends <NUM> of the fan blades <NUM>, may have a sharp decrease in spoke pitch angle, such as a decrease of about <NUM> degrees or more, such as from about <NUM>-<NUM> degrees to about <NUM>-<NUM> degrees for example, relative to the circumferential direction. Alternatively, or in addition, the camber angle of the radially outer portion of at least one of the spokes <NUM> may sharply increase, such as by at least about <NUM> degrees for example, from about <NUM>-<NUM> degrees to about <NUM>-<NUM> degrees and/or the chord of the radially outer portion of at least one of the spokes <NUM> may sharply increase by at least about <NUM>%, such as from about <NUM>%-<NUM>% to <NUM>% of the chord at the tip section.

As shown, the grille <NUM> additionally includes a plurality of partial spokes <NUM> extending inwardly from the outer wall <NUM> and arranged between pairs of adjacent spokes <NUM>. Although the partial spokes <NUM> are shown equidistantly spaced between each pair of adj acent spokes <NUM>, implementations where one or more of the partial spokes <NUM> is arranged at a non-central location between a pair of spokes <NUM> are also contemplated herein. A radial length of the partial spokes <NUM> is less than a radial length of the spokes <NUM>. Optionally, the radial length of the partial spokes <NUM> is less than <NUM>% of the radial length of the spokes <NUM>, and further may be less than <NUM>%, less than <NUM>%, or even less than <NUM>% of the radial length of the spokes <NUM>.

Because the airflow A provided to partial spokes <NUM> has the same flow conditions as the flow provided to a corresponding portion of the spokes <NUM> a configuration of the partial spokes <NUM> may be substantially identical to a configuration of the spokes at the same radial location (see <FIG>). For example, the spoke pitch angle, chord, and camber angle of the partial spokes <NUM> may be the same as the spoke pitch angle, chord, and camber angle of the spoke <NUM> at the same spanwise location.

With reference again to <FIG> and further reference to <FIG>, to enhance the structural rigidity of the outer wall <NUM>, a plurality of structural features <NUM>, such as ribs or tabs for example, may be arranged about the periphery of the exterior surface <NUM> of the outer wall <NUM>. The features <NUM> may be separate components attached to the outer wall <NUM> or may be integrally formed as a part of the outer wall <NUM>. The configuration of the structural features <NUM> may be selected based on the forces and/or stresses experienced at the outer wall <NUM>. The structural features <NUM> may be individual features, or alternatively, may be formed in groups as shown in the FIGS. Where the features <NUM> are clustered in groups, the features <NUM> within each group may be substantially identical or may vary. The individual features <NUM> or groups of features <NUM> may extend about only a portion, or alternatively, the entire of periphery of the outer wall <NUM>. Further, the features <NUM> or groups of features <NUM> may be continuously arranged or may be spaced at intervals about all or a portion of the periphery. Optionally, each feature <NUM> or group of features <NUM> is radially aligned with one of the plurality of spokes <NUM> or one of the plurality of partial spokes <NUM>, respectively.

The grille <NUM> includes additionally one or more elements <NUM> extending circumferentially about the hub <NUM>, between the hub <NUM> and the outer wall <NUM>. In the illustrated arrangement, the grille <NUM> includes a plurality of concentrically mounted circumferential elements <NUM> spaced equidistantly from one another and between the hub <NUM> and the outer wall <NUM>. However, implementations where the circumferential elements <NUM> are not equidistantly spaced or where a center of one or more of the circumferential elements <NUM> is offset from the fan axis X are also envisaged. A plurality of openings <NUM> are defined between adjacent circumferential elements <NUM>, radial spokes <NUM>, and partial spokes <NUM>. The size of the plurality of openings <NUM> may be selected to prevent the introduction of foreign objects or a finger into the fan assembly <NUM> via the grille <NUM>. However, it should be noted that the size of the openings <NUM> defined at least partially by the partial spokes <NUM> are smaller than the openings <NUM> defined between adjacent radial spokes <NUM> and circumferential elements <NUM>.

As shown, each of the circumferential elements <NUM> may be connected to each of the plurality of radial spokes <NUM>. Further, at least a portion of the circumferential elements <NUM> may be configured to overlap with the partial spokes <NUM> and may be similarly connected to each of the partial spokes <NUM>. Optionally, the hub <NUM>, stack diffuser outer wall <NUM>, spokes <NUM>, partial spokes <NUM>, and circumferential elements <NUM> are integrally formed as a single unitary component. In that case, the grille <NUM> may be manufactured via any suitable process, including but not limited to injection molding or additive manufacturing for example. Optionally, the grille <NUM> is formed from a non-metal material, such as plastic or composite for example. By using a plastic material, the potential for degradation, such as the formation of rust as a result of exposure to the elements (for example rain) is eliminated. However, implementations where the grille <NUM> is formed from a metal material are also envisaged.

A configuration of one or more of the circumferential elements <NUM> varies or is non-uniform about its circumference. For example, as best shown in <FIG>, a thickness of the circumferential elements <NUM>, measured parallel to the fan axis X, may be non-uniform to reduce the aerodynamic losses as the airflow passes over the circumferential elements <NUM>. The depth of one or more of the circumferential elements <NUM> directly adjacent a radial spoke <NUM> or partial spoke <NUM> may be increased relative to a portion of a circumferential element <NUM> arranged centrally between two radial spokes <NUM> or centrally between a partial spoke <NUM> and a radial spoke <NUM>. As shown, the thickness may taper from a first depth at a central portion of the circumferential element <NUM> to a second depth adjacent the spokes <NUM> and partial spokes <NUM>. Further, this tapered depth may be present at the upstream end of the circumferential elements <NUM>, facing the fan assembly <NUM>. Accordingly, the downstream end of each of the circumferential elements <NUM> may be substantially uniform about its periphery and arranged within a plane. However, other configurations of the circumferential elements <NUM> are contemplated herein.

As illustrated and described above, the grille <NUM> may be suitable for use with a coil unit <NUM>. , In certain instances, the grille <NUM> may be configured to satisfy all UL compliance requirements for outdoor fan grilles. For example, the grille may be formed from a UL approved material, satisfy UL finger protection requirements, and may support a structural load of <NUM> over a <NUM> ( <NUM> pounds over a <NUM> inches) diameter circle. Further, the performance of the grille <NUM> may be on par with (or better than) existing wire grilles and may provide a suitable replacement option for existing systems without negatively impacting the aerodynamic performance of the fan assembly or overall system efficiency.

Claim 1:
An integrated diffuser grille (<NUM>) for a coil unit (<NUM>) comprising:
a hub (<NUM>);
a stack diffuser wall (<NUM>);
a plurality of radial spokes (<NUM>) extending between the hub (<NUM>) and the stack diffuser wall (<NUM>);
a plurality of partial spokes (<NUM>) extending inwardly from the stack diffuser wall (<NUM>), wherein a radial length of the plurality of partial spokes (<NUM>) is less than a radial length of the plurality of spokes (<NUM>); and
a plurality of circumferential elements (<NUM>) arranged between the hub (<NUM>) and the stack diffuser wall (<NUM>), the plurality of circumferential elements (<NUM>) being connected to the plurality of radial spokes (<NUM>), at least one circumferential element of the plurality of circumferential elements (<NUM>) being connected to the plurality of partial spokes (<NUM>); wherein a cross-section of the plurality of radial spokes (<NUM>) has an airfoil-shape and wherein at least one of a spoke pitch angle, camber angle, and chord of the airfoil-shape varies over a radial length of the plurality of spokes (<NUM>);
the integrated diffuser grille (<NUM>) being characterised in that at least one circumferential element of the plurality of circumferential elements (<NUM>) has a non-uniform configuration about a circumference of the plurality of circumferential elements;
and in that a stacking line defined by a mid-chord of the airfoil-shape over the radial length of at least one of the plurality of radial spokes (<NUM>) is a straight line.