Patent Description:
Regulations in various regions around the world are requiring that refrigerant suppliers reduce distributions of high global warming potential (GWP) refrigerants. This presents an issue, however, in that new blends of low GWP refrigerants, such as A2L refrigerants, are often characterized as being mildly flammable. Thus, if an A2L refrigerant, for example, leaks into a cargo container interior through evaporator tubing, the leaked A2L refrigerant can create a mildly flammable environment that could ignite if a sufficient energy source exists.

While the potential ignition of leaked, mildly flammable refrigerant can be addressed by various options, such as the provision of safety systems, doing so is costly and time consuming.

<CIT> discloses a vehicle with a cargo space and a cooling device to cool the cargo area.

<CIT> discloses a refrigeration unit that is mounted to shield an opening formed in a container box from the outside and cools the inside air.

According to an aspect of the invention, a system is provided comprising a pod assembly and a fan, the pod assembly comprising an evaporator including evaporator tubes and return bend elements connecting corresponding evaporator tube ends. The pod assembly includes peripheral flanges which are attachable to a wall of a cargo area, a convex portion formed to define, with a portion of the wall, an interior to accommodate the evaporator tubes and the fan, the interior being fluidly communicative with the cargo area through an inlet and an outlet defined in the wall and the fan drives air flow from the inlet to the outlet and through the evaporator tubes and plate sections provided with multiple apertures, the plate sections being respectively secured to opposite end sections of the evaporator tubes and respective local portions of the peripheral flanges and the convex portion to isolate the return bend elements from the interior. The return bend elements are provided at the opposite end sections of the evaporator tubes. Respective outer planes of the plate sections are coplanar with respective outermost planes of the opposite end sections of the evaporator tubes. The multiple apertures sealably surround each of the evaporator tubes.

The return bend elements include return bends and brazed joints that connect the return bends to the corresponding ends of the two or more evaporator tubes.

In accordance with additional or alternative embodiments, the peripheral flanges form a polygonal profile and the convex portion includes rounded edges.

In accordance with additional or alternative embodiments, the interior includes a lower section defined between the inlet and the evaporator tubes, an upper section defined between the fan and the outlet and a central section defined between evaporator tubes and the fan.

In accordance with additional or alternative embodiments, the plate sections are respectively formed to define apertures through which the return bend elements are connectable with the corresponding evaporator tube ends.

In accordance with additional or alternative embodiments, the plate sections respectively define, with respective distal portions of the peripheral flanges and the convex portion, distal interiors isolated from the interior and the distal portions of the convex portion define apertures through which the distal interiors are communicative with an exterior of the cargo area.

In accordance with additional or alternative embodiments, the convex portion includes removable panels.

According to another aspect of the invention, a transport refrigeration unit (TRU) is provided and includes a wall defining an inlet and an outlet between a cargo area and an exterior, and a system as defined above. The pod assembly includes an evaporator, peripheral flanges attachable to the wall, a convex portion defining, with a portion of the wall, an interior communicative with the cargo area through the inlet and the outlet and configured to accommodate the evaporator and the fan that drives air flow from the inlet and to the outlet through the evaporator and plate sections respectively secured to opposite end sections of evaporator tubes of the evaporator and respective local portions of the peripheral flanges and the convex portion to divide the interior into a first interior configured to accommodate the evaporator tubes and the fan and second interiors isolated from the first interior and configured to accommodate return bend elements of the evaporator. The return bend elements are provided at the opposite end sections of the evaporator tubes. Respective outer planes of the plate sections are coplanar with and sealably surround respective outermost planes of the opposite end sections of the evaporator tubes.

The return bend elements include return bends and brazed joints that connect the return bends to corresponding ends of the two or more evaporator tubes.

In accordance with additional or alternative embodiments, the peripheral flanges form a polygonal profile and the convex portion comprises rounded edges.

In accordance with additional or alternative embodiments, a width of the first interior is equal to or slightly less than a width of the evaporator tubes.

In accordance with additional or alternative embodiments, the first interior includes a lower section defined between the inlet and the evaporator tubes, an upper section defined between the fan and the outlet and a central section defined between evaporator tubes and the fan.

In accordance with additional or alternative embodiments, the plate sections are respectively formed to define apertures through which the return bend elements are connectable with the corresponding evaporator tubes.

In accordance with additional or alternative embodiments, the distal portions of the convex portion define apertures through which the second interiors are communicative with an exterior of the cargo area.

The subject matter, which is regarded as the invention, is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:.

As will be described below, a pod is provided to isolate piping, valves, return bends and other brazed joints from exposure to the outdoor ambient section of a transport refrigeration unit. The pod includes an enclosure with covers so that if a leak occurs, the leaked fluid cannot be pulled into the air stream by the evaporator fan. A refrigerant and condensate drain would allow leaked fluid to flow out of the enclosed area to the outside of the cargo storage area.

With reference to <FIG>, a trailer <NUM> is provided and is attachable to a truck for transportation of various goods. The trailer <NUM> includes a body <NUM> that defines an interior or a cargo area <NUM> in which the various goods can be stowed during transportation. To an extent that these goods need to be kept in an air conditioned environment, such as where the goods include perishable items, the trailer <NUM> may further include a transport refrigeration unit (TRU) <NUM>. The TRU <NUM> is attachable a portion of the body <NUM>, such as a front of the body <NUM>, and is configured to draw heated air in from the cargo area <NUM>, to cool the heated air and to exhaust cooled air back into the cargo area <NUM>. Within the TRU <NUM>, the cooling is accomplished by flowing the heated air over and across evaporator tubing of an evaporator. The evaporator tubing is charged with refrigerant at a lower temperature than the heated air such that, as the heated air flows over and across the evaporator tubing, the refrigerant removes heat from the heated air.

While several different types of refrigerant can be used, some refrigerants tend to have relatively high GWP whereas others tend to have relatively low GWP and, as regulations change, the use of the relatively low GWP refrigerants is becoming increasingly required. This being the case, with reference to <FIG>, it is seen that the relatively low GWP refrigerants tend to be more flammable than the relatively high GWP refrigerants. Therefore, where the relatively low GWP refrigerants are used in TRU applications, it is typically necessary to prevent leakage of the relatively low GWP refrigerants into the flows moving through the TRU <NUM> and/or into the cargo area <NUM>.

With continued reference to <FIG> and with additional reference to <FIG>, a conventional pod <NUM> can be provided for use with the TRU <NUM> to constrain and control flows of heated air from the cargo area <NUM> through the TRU <NUM> (see <FIG>). The conventional pod <NUM> is attachable along its periphery to a wall of the cargo area <NUM> and has a convex portion that forms interior regions <NUM> and <NUM> that can respectively accommodate an evaporator of the TRU <NUM> and a fan that drives airflow from the cargo area <NUM>, through an inlet defined in the wall, through the evaporator and back into the cargo area <NUM> through an outlet defined in the wall. As shown in <FIG>, the interior region <NUM> in particular has sufficient room to accommodate an entirety of the evaporator, including the evaporator tubing and the return bend elements. The evaporator tubing is generally provided as substantially straight tubes that run across a substantial length of the evaporator. The return bend elements include return bends that connect corresponding ends of two or more evaporator tubes to one another and braze joints by which the return bends actually connect to the corresponding ends of the two or more evaporator tubes as well as additional piping and valves.

Refrigerant leaks from the evaporator tubing are uncommon, but refrigerant leaks from the return bend elements are a present issue. Thus, since the interior region <NUM> of the conventional pod <NUM> accommodates the return bend elements, leaks of refrigerant (i.e., mildly flammable, low GWP refrigerants) can occur and result in leaked refrigerant entering into the flows of air through the TRU <NUM> or into the cargo area <NUM> directly.

With reference to <FIG>, a transport refrigeration unit (TRU) <NUM> is provided and includes a cargo area wall <NUM> (i.e., for the cargo area <NUM> of <FIG>), an evaporator <NUM> and a pod <NUM>. The cargo area wall <NUM> is formed to define an inlet <NUM> and an outlet <NUM> that are each fluidly communicative with the cargo area <NUM>. The evaporator <NUM> includes evaporator tubes <NUM> (see <FIG>) and return bend elements <NUM>. The evaporator tubes <NUM> are substantially straight and extend along a substantial length of the evaporator <NUM>. The return bend elements <NUM> are provided at opposite end sections <NUM> and <NUM> of the evaporator tubes <NUM> and include return bends that fluidly connect corresponding ends of two or more evaporator tubes <NUM>, brazed joints that actually connect the return bends to the evaporator tubes <NUM>, feeder piping and valves.

The pod <NUM> includes peripheral flanges <NUM> that are attachable to the cargo area wall <NUM>, a convex portion <NUM> and plate sections <NUM>. The convex portion <NUM> is attached to the peripheral flanges <NUM> and is formed to define, with a corresponding portion <NUM> of the cargo area wall <NUM>, an interior <NUM> (see <FIG>). The interior <NUM> is communicative with the cargo area <NUM> through the inlet <NUM> and the outlet <NUM> and is configured and sized to accommodate the evaporator <NUM> and a fan <NUM>. The fan <NUM> is operable to drive air flow from the inlet <NUM> and to the outlet <NUM> through the evaporator <NUM>. The plate sections <NUM> are respectively secured to the opposite end sections <NUM> and <NUM> of the evaporator tubes <NUM> and to respective local portions of the peripheral flanges <NUM> and the convex portion <NUM>. The plate sections <NUM> thus divide the interior <NUM> into a first interior <NUM> and second interiors <NUM>.

The first interior <NUM> is configured and sized to accommodate the evaporator tubes <NUM> and the fan <NUM>. Each of the second interiors <NUM> is isolated from a corresponding side of the first interior <NUM> and each of the second interiors <NUM> is sized and configured to accommodate the corresponding return bend elements <NUM> as well as the valves and other required piping to connect the evaporator <NUM> to the refrigeration system.

The plate sections <NUM> therefore effectively isolate the return bend elements <NUM> from the first interior <NUM>. As such, leakage of refrigerant from the return bend elements <NUM> is prevented from flowing into the first interior <NUM> and from flowing into the cargo area <NUM> directly or indirectly.

In accordance with embodiments, the peripheral flanges <NUM> form a form a polygonal profile <NUM> with a relatively wide, lower section that is configured and sized to surround the evaporator <NUM> and a relatively narrow, upper section that is configured and sized to surround the fan <NUM>. As shown in <FIG>, the convex portion <NUM> includes a forward body <NUM>, sidewalls <NUM> extending from the peripheral flanges <NUM> to the forward body <NUM>, rounded edges <NUM> at the peripheral flanges <NUM> and rounded edges <NUM> at the forward body <NUM>. The sidewalls <NUM> may be sized such that a width of the first interior <NUM> is equal to or slightly less than a width of the evaporator tubes <NUM>.

As shown in <FIG>, the first interior <NUM> includes a lower section <NUM>, an upper section <NUM> and a central section <NUM>. The lower section <NUM> is defined between the inlet <NUM> and the evaporator tubes <NUM>. The upper section <NUM> is defined between the fan <NUM> and the outlet <NUM>. The central section <NUM> is defined between the evaporator tubes <NUM> and the fan <NUM> and is fluidly interposed between the lower section <NUM> and the upper section <NUM>.

As shown in <FIG> and with additional reference to <FIG>, respective outer planes <NUM> of the plate sections <NUM> are substantially coplanar with respective outermost planes of the opposite end sections <NUM> and <NUM> of the evaporator tubes <NUM>. Thus, substantial entireties of the return bend elements <NUM> can be isolated from the first interior <NUM>. The plate sections <NUM> are provided with multiple apertures <NUM> (see <FIG>). The multiple apertures <NUM> sealably surround each individual evaporator tube <NUM> in an event the evaporator tubes <NUM> have interstitial spaces between them.

As shown in <FIG>, distal portions of the convex portion <NUM> (i.e., the portions of the convex portion <NUM> that surround the second interiors <NUM>) may be formed to define drain apertures <NUM>. Leaked refrigerant flowing out of the return bend elements <NUM>, which is isolated from the first interior <NUM> within each of the second interior <NUM> can flow out of the second interiors <NUM> and toward an exterior via the drain apertures <NUM>.

With reference to <FIG>, the convex portion <NUM> may include removable panels <NUM> at various locations including locations at which the removable panels <NUM> would provide access to the first interior <NUM> and locations at which the removable panels <NUM> would provide access to the second interiors <NUM> and the return bend elements <NUM> (see <FIG>).

With reference to <FIG>, alternative embodiments of the pod <NUM> are provided in which the pod <NUM> itself is configured to isolate at least the return bend elements <NUM> from the interior <NUM>. As shown in <FIG>, the pod <NUM> is generally formed as described above to define, with the corresponding portion <NUM> (see <FIG>) of the cargo area wall <NUM>, the interior <NUM>. The interior <NUM> is configured to accommodate the evaporator <NUM>, the fan <NUM> and the air flow generated by the fan <NUM> through the evaporator <NUM>. The opposite sides <NUM>, <NUM> of the pod <NUM> are tapered around the opposite end sections <NUM> and <NUM> of the evaporator tubes <NUM> such that pod <NUM> itself is configured to isolate the return bend elements <NUM> from the interior <NUM>.

In accordance with embodiments and, as shown in <FIG>, the pod <NUM> is formed to define a first aperture <NUM> and a second aperture <NUM> (see <FIG> and the accompanying text for similar configurations). The end sections <NUM> of the evaporator tubes <NUM> extend through the first aperture <NUM> such that the return bend elements <NUM> associated with the end sections <NUM> are isolated as a whole from the interior <NUM>. The end sections <NUM> of the evaporator tubes <NUM> extend through the second aperture <NUM> such that the return bend elements <NUM> associated with the end sections <NUM> are isolated as a whole from the interior <NUM>.

In accordance with embodiments and, as shown in <FIG>, the pod <NUM> is formed to define first apertures <NUM> and second apertures <NUM> (see <FIG> and the accompanying text for similar configurations). The return bend elements <NUM> associated with the end sections <NUM> respectively extend through corresponding ones of the first apertures <NUM> and are thus isolated on an individual basis from the interior <NUM>. The return bend elements <NUM> associated with the end sections <NUM> respectively extend through corresponding ones of the second apertures <NUM> and are thus isolated on an individual basis from the interior <NUM>.

Technical effects and benefits of the present invention are an elimination of a need for expensive ventilation and circulation systems that might otherwise be effectively required by regulations relating to mildly flammable, low GWP refrigerants. The pod described herein is designed such that no leak points are exposed inside a cargo box and may reduce potential false alarms, system shutdowns and loss of cargo events.

Claim 1:
A system comprising a pod assembly and a fan (<NUM>), the pod assembly comprising:
an evaporator (<NUM>) comprising evaporator tubes (<NUM>) and return bend elements (<NUM>) connecting corresponding evaporator tube ends, the return bend elements (<NUM>) comprising return bends and brazed joints that connect the return bends to the corresponding ends of the two or more evaporator tubes (<NUM>);
peripheral flanges (<NUM>) which are attachable to a wall (<NUM>) of a cargo area (<NUM>);
a convex portion (<NUM>) formed to define, with a portion of the wall (<NUM>), an interior (<NUM>) accommodating the evaporator tubes (<NUM>) and the fan (<NUM>), the interior (<NUM>) being able to be fluidly communicative with the cargo area (<NUM>) through an inlet (<NUM>) and an outlet (<NUM>) defined in the wall (<NUM>), and the fan (<NUM>) being arranged to drive air flow from the inlet (<NUM>) to the outlet (<NUM>) and through the evaporator tubes (<NUM>); and
plate sections (<NUM>) provided with multiple apertures (<NUM>), the plate sections (<NUM>) being respectively secured to opposite end sections (<NUM>, <NUM>) of the evaporator tubes (<NUM>), and respective local portions of the peripheral flanges (<NUM>) and the convex portion (<NUM>) to isolate the return bend elements (<NUM>) from the interior (<NUM>);
wherein respective outer planes (<NUM>) of the plate sections (<NUM>) are coplanar with respective outermost planes of the opposite end sections (<NUM>, <NUM>) of the evaporator tubes (<NUM>); and the multiple apertures (<NUM>) sealably surround each of the evaporator tubes (<NUM>); and
characterised in that the return bend elements (<NUM>) are provided at the opposite end sections (<NUM>, <NUM>) of the evaporator tubes (<NUM>).