Patent Description:
Refrigerated trucks, trailers, and containers are commonly used to transport perishable cargo, such as, for example, produce, meat, poultry, fish, dairy products, cut flowers, pharmaceuticals and other fresh or frozen perishable products. Conventionally, transport refrigeration systems include a transport refrigeration unit having a refrigerant compressor, a condenser with one or more associated condenser fans, an expansion device, and an evaporator with one or more associated evaporator fans, which are connected via appropriate refrigerant lines in a closed loop refrigerant circuit. Air or an air/gas mixture is drawn from the interior volume of the cargo box by means of the evaporator fan(s) associated with the evaporator, passed through the airside of the evaporator in heat exchange relationship with refrigerant whereby the refrigerant absorbs heat from the air, thereby cooling the air. The cooled air is then supplied back to the cargo box.

Although the existing evaporator fan and bracket for mounting the evaporator fan are suitable, these components may be optimized to reduce the inefficiencies in the airflow provided to the fan.

<CIT> discloses a heat exchanger including a plurality of tube elements including a first tube segment and a second tube segment and at least one return bend connecting an end of the first tube segment to the second tube segment such that the plurality of tube elements and the at least one return bend define a fluid flow path of the heat exchanger. The at least one return bend is positioned within a cavity isolated from a remainder of the heat exchanger.

<CIT> discloses an evaporator air management system for trailer refrigeration systems, including an electrically powered, vertical axis, axial flow fan, arranged so as to draw air through a horizontally mounted evaporator coil. The flow is then driven upward through a nozzle and discharged into the trailer. The nozzle shape graduates from a circular cross-section to a wide-aspect ratio rectangular cross-section, while turning through <NUM>°. The preferred choice of axial flow fan for the invention is the vane-axial type incorporating outlet guide vanes. Provision is made for a single fan-nozzle configuration which may be either centered or transversely off-set with respect to the evaporator coil. An additional option provides for an arrangement with a pair of side-by-side fan-nozzles.

<CIT> discloses a power package, comprising a diesel engine and a permanent magnet generator, accommodated in a lower section of a main support frame mounted on a front wall of a cargo container. A compressor, a pair of vane axial fan units, a pair of centrifugal fan units and auxiliary centrifugal fan units are driven by the power supply from the generator. A mounting bracket is formed to the main support frame for mounting the power package. The compressor, is mounted within the mounting bracket above and to one side of the diesel engine and the generator. A condenser evaporator is mounted on the forward compartment and an evaporator heat exchanger is mounted on the rear compartment of the upper section. A condenser air passage is formed behind the condenser heat exchanger and an evaporation air passage is formed behind the evaporator heat exchanger. The condenser heat exchanger is connected to the discharge side of the compressor and the evaporator heat exchanger is connected to the suction side of the compressor. A refrigerant line having an expansion value connects both the heat exchangers. The vane axial fan units are mounted in the bottom of the condenser air passage for drawing ambient air through the condenser heat exchanger, and discharging the drawn air into the lower section of the main support frame for cooling the power package and the compressor. The electrically driven centrifugal fan units are mounted on top of the rear compartment of the upper section for drawing in the air from container through the evaporator heat exchanger and discharging back to the container. The centrifugal fans are arranged to turn in opposite direction to direct the conditioned air along the top wall of the container. The auxiliary centrifugal fan is provided for the evaporation heat exchanger side, which, with the two centrifugal fans, discharges to the three zones of the container. The vane axial fans are provided with a diffuser each in the discharge side.

In accordance with the present invention, there is provided a transport refrigeration unit as set out in independent claim <NUM>. Preferred embodiments of the present invention are laid down in the appended dependent claims.

A detailed description of one or more embodiments of an exemplary transport refrigeration system are presented herein by way of exemplification and not limitation with reference to the Figures.

With reference now to <FIG>, an exemplary transport refrigeration system <NUM> is illustrated. In the illustrated, non-limiting embodiment, the transport refrigeration system <NUM> is shown as a trailer system. As shown, the transport refrigeration system <NUM> includes a cargo container or trailer <NUM>. The cargo container <NUM> may be towed or otherwise transported by a tractor <NUM> including an operator's compartment or cab <NUM> an engine or other power source, such as a fuel cell for example, which acts as the drivetrain system of the tractor <NUM>. A transport refrigeration unit (TRU) <NUM> is configured to maintain cargo located within the internal cargo area <NUM> (see <FIG>) of the container <NUM> at a selected temperature by cooling the cargo space of the container <NUM>. As shown, the TRU <NUM> is typically mounted at the front wall <NUM> of the container <NUM>. Together, the TRU <NUM> and the cargo container <NUM> may form a transport refrigeration system <NUM>. However, embodiments where the transport refrigeration system <NUM> is additionally interpreted to include the tractor <NUM> are also contemplated herein. Further, it should be appreciated by those of skill in the art that embodiments described herein may be applied to any transport refrigeration system such as, for example shipping containers that are shipped by rail, sea (via a watercraft), or any other suitable container, without use of a tractor <NUM>.

As best shown in <FIG>, the TRU <NUM> includes an exterior condenser <NUM> that projects forward of the front wall <NUM> and an interior evaporator section <NUM> disposed within the front wall <NUM> and that projects rearwardly toward the cargo area <NUM> of the trailer <NUM>. With reference now to <FIG> and <FIG>, an example of an evaporator section <NUM> of the TRU <NUM> is illustrated in more detail. The evaporator section <NUM> includes an inlet <NUM> that receives return air from the cargo area <NUM> of the trailer body <NUM>. Mounted within a lower portion of the evaporator section <NUM> is an evaporator coil <NUM>. The evaporator coil <NUM> may be mounted at an angle, as shown, to increase the effective surface area and assist in condensate drainage. However, embodiments where the evaporator coil <NUM> is mounted with a different configuration are also within the scope of the invention.

Mounted on a support deck of the evaporator section <NUM> is a fan and nozzle unit <NUM> having one or more interior regions. Disposed within an interior region <NUM> adjacent the bottom of the fan and nozzle unit <NUM> is an axial flow fan <NUM> and an electric drive motor <NUM> positioned vertically above the fan <NUM>. The axes of the fan <NUM> and the drive motor <NUM> are vertically oriented. The nozzle <NUM> of the fan and nozzle unit <NUM> extends from adjacent the fan <NUM> to an outlet <NUM>. In the illustrated, non-limiting embodiment, a first end <NUM> of the nozzle <NUM>, is generally rounded so as to surround the fan <NUM>. Moving from the first end <NUM> to a second end <NUM>, the nozzle <NUM> decreases in cross-sectional area and gradually transitions from the circular shape to a wide aspect ratio rectangular cross-section, while also turning approximately <NUM> degrees to a rearwardly facing outlet <NUM>.

During operation, the return air from the cargo area <NUM> of the trailer <NUM> is drawn into the inlet <NUM>, passed through the evaporator coil <NUM> where the air is cooled, and is then blown out of the outlet <NUM> toward the rear of the cargo area <NUM>, to cool the cargo. It should be understood that the TRU <NUM> illustrated and described herein is intended as an example only. Accordingly, other transport refrigeration units having an inlet <NUM> for receiving air from the cargo area <NUM> of the container <NUM> and an outlet <NUM> for discharging cool air into the cargo area <NUM> of the container <NUM> are also within the scope of the invention.

With reference now to <FIG> (which depict examples useful for understanding the invention), the axial flow fan <NUM> mounted within an interior region <NUM> of the fan and nozzle unit <NUM> is illustrated in more detail. As shown, the axial flow fan <NUM> includes a fan inlet including a stator assembly <NUM> having a stator hub <NUM>, a stator shroud <NUM>, and a plurality of stator vanes <NUM> extending radially outwardly from the centrally located stator hub <NUM> to the stator shroud <NUM>. Optionally, the stator assembly <NUM> includes a mounting flange <NUM> integrally formed with the stator shroud <NUM>. As shown, the mounting flange <NUM> is arranged adjacent a first, upstream end of the stator assembly <NUM> and extends radially outwardly from the stator shroud <NUM>. The mounting flange <NUM> may extend about an entire periphery of the stator shroud <NUM>, or alternatively, may be arranged at only a portion of the periphery of the stator shroud <NUM>. Furthermore, radial length of the mounting flange <NUM> may vary about the periphery of the stator shroud <NUM>. As a result, the mounting flange <NUM> may have a non-circular shape. Optionally, a plurality of ribs <NUM> extend between an upper surface of the mounting flange <NUM> and the outer periphery of the stator shroud <NUM>. Inclusion of such ribs <NUM> may increase the rigidity or stiffness of the stator assembly <NUM>. The stator assembly <NUM> may be formed from any suitable material including, but not limited to a metal material and a composite material for example. Optionally, the composite material is an injection molded glass filled composite.

A mounting bracket <NUM> is operable to mount the stator assembly <NUM> within the interior region <NUM> of the fan and nozzle unit <NUM>. Optionally, the mounting bracket <NUM> is formed as a unitary component from a composite material, such as an injection molded glass filled composite material. The mounting bracket <NUM> includes a body having a main support member <NUM> having a generally planar first surface <NUM>. The mounting flange <NUM> of the stator assembly <NUM> may be positionable in overlapping arrangement with the first surface <NUM> of the mounting bracket <NUM>. Accordingly, a through hole <NUM> is formed in the main support member <NUM> in axial alignment with the stator assembly <NUM>. The through hole <NUM> may be substantially equal in diameter to the interior of the stator shroud <NUM> such that a uniformly sized fluid flow path is defined therethrough. The first surface <NUM> of the mounting bracket <NUM> may be equal to or may be generally larger than mounting flange <NUM>, as shown. In such embodiments, one or more features <NUM> may protrude from the first surface <NUM> to facilitate proper positioning of the mounting flange <NUM> relative to the mounting bracket <NUM>. In the illustrated, non-limiting embodiment, several features <NUM> extend at various locations generally orthogonally from the first surface <NUM> to form at least a partial boundary or border surrounding the mounting flange <NUM>.

The body additionally includes at least one sidewall <NUM> extending from the main support member <NUM>. In the illustrated, non-limiting embodiment, the at least one sidewall <NUM> is integrally formed with a second, opposite surface <NUM> of the main support member <NUM> and extends generally downwardly therefrom. The at least one sidewall <NUM> may be connected to the surface <NUM> directly adjacent to the through hole <NUM> or at another portion of the surface <NUM>. As shown, the at least one sidewall <NUM> includes two sidewalls: a first sidewall <NUM> arranged adjacent a first side <NUM> of the body and a second sidewall <NUM> arranged adjacent a second opposite side <NUM> of the body. The first and second sidewalls <NUM> may be substantially identical to one another, such as mirror images of one another (symmetrical) about a central plane.

Optionally, each sidewall <NUM> extends between a front end <NUM> of the main support member <NUM> and a back end <NUM> of the main support member. An axial length of the sidewall <NUM> between the front and back ends <NUM>, <NUM> may be constant, or alternatively, may vary. In the illustrated, non-limiting embodiment, the axial length of the at least one sidewall <NUM> is shortest near the front end <NUM> of the main support member <NUM> and may gradually increase towards the back end <NUM> of the main support member <NUM>. The at least one sidewall <NUM> may have an angle or bend <NUM> formed therein such that the at least one sidewall <NUM> wraps about a portion of the back end <NUM>. In such embodiments, the axial length of the sidewall <NUM> may gradually increase from the bend <NUM> towards the distal end <NUM> of the sidewall <NUM>. Accordingly, the maximum axial length of the sidewall <NUM> may be at or near the distal end <NUM> of the sidewall.

The at least one sidewall <NUM> has an opposing front surface <NUM> and back surface <NUM>. In the illustrated, non-limiting embodiment, the back surface <NUM> of the at least one sidewall <NUM> is positionable in contact with a corresponding surface within the interior <NUM> of the fan and nozzle unit <NUM>. To facilitate installation and proper positioning of the body within the fan and nozzle unit <NUM>, the back surface <NUM> may be substantially complementary to the surface of the fan and nozzle unit <NUM>. With such a complementary configuration, contact between the surface of the fan and nozzle unit <NUM> and the back surface <NUM> of the sidewall <NUM> may be substantially uniform over the back surface <NUM> of the sidewall <NUM>. Optionally, at least one feature <NUM> extends between the back surface <NUM> of the sidewall <NUM> and the main support member <NUM>. Inclusion of these features <NUM>, such as ribs for example, provides added strength and rigidity to the sidewall <NUM>. In embodiments including these features, contact with the fan and nozzle unit <NUM> may be uniform about the features <NUM> extending from the back surface <NUM>.

The front surface <NUM> of the at least one sidewall <NUM> is substantially smooth to minimize the formation of any interferences within the fluid flow path leading towards the fan <NUM>. Further, in the illustrated, non-limiting embodiment, the front surface <NUM> of the sidewall <NUM> is contoured to direct flow from the evaporator section <NUM> towards an inlet of the fan <NUM>. As shown, the front surface <NUM> may be formed with a generally convex curvature that curves outwardly from a position adjacent to the through hole <NUM>, similar to a bell mouth shape. Accordingly, a diameter defined by the plurality of sidewalls <NUM> gradually increases from the smallest diameter at a position adjacent to the main support member <NUM> to a maximum diameter defined near the free ends of the sidewalls <NUM>. Optionally, shown in <FIG>, at least one flow feature <NUM>, such as a rib, guide, or flow shaping protrusion extends from the front surface <NUM> towards a center defined by the at least one sidewall <NUM>. Inclusion of these flow features <NUM>, may assist in directing the flow output from the evaporator coil towards the center of the mounting bracket <NUM> and the inlet of the axial fan <NUM>.

One or more fasteners <NUM> may be used to affix the stator assembly <NUM> to the mounting bracket <NUM>. Optionally, one or more cavities <NUM> may be formed in the front surface <NUM> of each sidewall <NUM>. In the illustrated, non-limiting embodiment, the cavity <NUM> provides access to a fastener <NUM> operable to couple the main support member <NUM> of the mounting bracket <NUM> to the mounting flange <NUM> of the stator assembly <NUM>. However, embodiments that have a continuous surface absent a cavity <NUM> are also contemplated herein. As shown in <FIG>, the mounting bracket <NUM> may include a cover <NUM> removably positionable in overlapping arrangement with each cavity <NUM> to form a smooth front surface <NUM> thereat. For example, the cover <NUM> may connect to the sidewall <NUM> via a snap fit or press-fit connection. Alternatively, the cavities <NUM> may be absent from the sidewalls <NUM>. Further, the front surface <NUM> may have one or more rivets or openings through which fasteners operable to mount the mounting bracket <NUM> may be installed.

The body of the mounting bracket <NUM> may include a front wall <NUM> extending from the front end <NUM> at an angle relative to the main support member <NUM>. The axial length of the front wall <NUM> is only a portion of the axial length of the sidewalls. However, embodiments where the axial length of the front wall <NUM> is extended are also contemplated herein. In the illustrated, non-limiting embodiment, the front wall <NUM> is oriented substantially parallel to the axis of the fan, and therefore generally perpendicular to the planar surface <NUM>. However, embodiments where the front wall <NUM> is arranged at another angle are also within the scope of the invention. Optionally, to increase the rigidity of the structure, a honeycomb-like pattern is formed at a surface of the front wall <NUM>, such as the surface facing away from the mounting bracket <NUM>.

As shown in <FIG>, the front wall <NUM> may include a cutout <NUM>, such as extending downwardly from the planar first surface <NUM>, to facilitate installation of the fan <NUM>. Although a u-shaped cutout is illustrated in the FIG. , it should be understood that a cutout having another shape is also within the scope of the invention. However, embodiments of the of the mounting bracket <NUM> where the front wall <NUM> does not include a cutout are also contemplated herein.

The mounting bracket <NUM> may additionally include one or more mounting members positionable in overlapping arrangement with a surface of the fan and nozzle unit <NUM>. The mounting members may be integrally formed with the body, or alternatively, may be a separate component connected to the main support member <NUM>. In the illustrated, non-limiting example, a first mounting member 102a extends from the first surface <NUM>, near the front end <NUM> and the first side <NUM> of the main support member <NUM>. Alternatively, or in addition, a second mounting member 102b extends from the first surface <NUM>, near the front end <NUM> and the second side <NUM> of the main support member <NUM>. As shown, each mounting member 102a, 102b has three surfaces extending generally perpendicular to one another to form a corner-like configuration. In such embodiments each mounting member 102a, 102b is positioned over a corresponding corner formed in the fan and nozzle unit <NUM>. However, it should be understood that a mounting member 102a, 102b having another suitable configuration that overlaps one or more surfaces of the fan and nozzle unit <NUM> are also contemplated herein. The at least one mounting member 102a, 102b may be attached to the fan and nozzle unit <NUM> via one or more fasteners <NUM>, such as screws or bolts for example.

The axial fan <NUM> is supported by the stator assembly <NUM> mounted to the first surface <NUM> of the mounting bracket <NUM>. Accordingly, the position of the axial fan <NUM> may be dependent on the height of the mounting members 102a, 102b relative to the first surface <NUM> of the mounting bracket <NUM>. Accordingly, the height of the mounting members 102a, 102b may be adjusted to position the axial fan <NUM> at a specific distance from the plenum or from the heat exchanger coil <NUM>. In an embodiment, the axial distance between the top of the mounting members 102a, 102b and the first surface <NUM> is between about <NUM> and about <NUM>.

A mounting bracket <NUM> as illustrated and described herein enhances the air flow towards the fan, without requiring any changes to the existing contour of the fan and nozzle unit <NUM>. Further, although the mounting bracket <NUM> is illustrated and described herein with respect to an evaporator coil, it should be appreciated that the mounting bracket may be adapted for use with any heat exchanger, such as condenser <NUM> for example.

Claim 1:
A transport refrigeration unit (<NUM>) comprising:
a fan and nozzle unit (<NUM>);
a heat exchanger coil (<NUM>);
an axial fan (<NUM>) having a vertically oriented fan axis, the axial fan (<NUM>) being positioned within the fan and nozzle unit (<NUM>) to draw air through the heat exchanger coil (<NUM>) and discharge the air vertically upwards; and
a mounting bracket (<NUM>) for mounting the axial fan (<NUM>) in the fan and nozzle unit (<NUM>) comprising:
a main support member (<NUM>) having an opposing first surface (<NUM>) and second surface (<NUM>) and a through hole (<NUM>); and being characterized by
at least one sidewall (<NUM>) integrally formed with and extending from the second surface (<NUM>), the at least one sidewall (<NUM>) having a smooth front surface (<NUM>), wherein a curvature of the front surface (<NUM>) facilitates an air flow towards a fan inlet.