Patent Application
20150202945
The invention relates generally to transport refrigeration systems and, more particularly, to an evaporator air management system of a transport refrigeration system.
Transport refrigeration systems are composed of a power system, refrigeration circuiting, air management systems, and a control system, which are all packaged in a unit mounted to a transport device, such as a trailer for example. The air management system circulates air through a load in the trailer and back through the evaporator coil, which subsequently removes heat from the air stream and thereby cools the cargo.
In conventional transport refrigeration systems, the flow distribution of the air discharge from the air management system is dependent on the velocity of the air as well as other flow characteristics. Because the resulting flow distribution is generally non-uniform, the cargo throughout the trailer is not cooled evenly, which may compromise the quality of the cargo. In some transport refrigeration systems, an attachment extends from the supply air discharge, such as a chute or duct for example. These attachments are typically supported by the ceiling and more uniformly distribute the air throughout the length of the trailer. However, the inclusion of a conventional chute or duct in a trailer impedes the loading and unloading of cargo in the trailer, such that the chute or duct is frequently damaged during such processes. The chute or duct may also become fouled with dirt, cargo residue, and other undesirable material. In addition, inclusion of a chute or duct decreases the air discharge supply and negatively impacts the performance of the evaporator air management system.
According to one embodiment of the invention, an airflow supply duct for use in a transportation refrigeration trailer is provided including an inlet portion adjacent a first end and an outlet portion adjacent a second opposite end. A generally curvilinear central portion is disposed between the inlet portion and the outlet portion. The inlet portion, the central portion, and the outlet portion form an interior flow path. The airflow supply duct has a rectangular cross-section having an approximately uniform cross-sectional area along a length of the airflow duct. A height and width of the airflow supply duct vary along the length of the airflow supply duct such that a ration of the width to the height at the second end is greater than the ration of the width to the height at the first end.
According to another aspect of the invention, a transportation refrigeration trailer having a plurality of walls including a front wall and a ceiling, wherein a transportation refrigeration unit is located without one of the plurality of walls and includes a discharge opening facing the interior of the trailer is provided include an airflow supply duct. The airflow supply duct is disposed within the interior of trailer such that a first end is coupled to the transportation refrigeration unit adjacent the discharge opening. The second end of the airflow supply duct is coupled to the ceiling. The airflow supply duct provides at least one flow path for air from the transportation refrigeration unit to the interior of the trailer. The airflow supply duct has a rectangular cross-section having an approximately uniform cross-sectional area along a length of the airflow supply duct. A height and width of the airflow supply duct vary along the length of the airflow supply duct such that a ratio of the width to the height at the second end is greater than the ratio of the width to the height at the first end.
These and other advantages and features will become more apparent from the following description taken in conjunction with the drawings.
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:
Referring to
An exemplary evaporator section 40 of the transportation refrigeration unit 20 is illustrated in
Referring now to
To circulate air throughout the full length of the trailer 10, the airflow supply duct 100 should have a length L in the range of about 3% to 30% of the length of the trailer 10. In one embodiment, the airflow supply duct 100 has a length L of about 12% of the length of the trailer 10. The airflow supply duct 100 includes a rectangular cross-section having an approximately constant area; the cross-sectional area may have a tolerance of about ±15%. Both the width W and the height H of the airflow supply duct 100 vary along the length L of the airflow supply duct 100, giving the airflow supply duct 100 a thin, wide profile. The width W and height H at the first end 102 are approximately equal to the width and height of the opening 58 of the nozzle 56. The width W gradually increases along the length L of the airflow supply duct 100 to form a generally flared second end 104. The width W at the second end 104 of the airflow supply duct 100 may be in the range of about 35% to 70% of the width of the trailer 10. In one embodiment, the width W of the second end 104 of the airflow supply duct 100 is about 42% of the width of the trailer 10.
The height H of the airflow supply duct 100 decreases from the first end 102 over the length L of the airflow supply duct 100. The height H at the second end 104 of the airflow supply duct 100 may be in the range of about 1% to 4% of the height of the trailer 10. In one embodiment, the second end 104 of the airflow supply duct 100 has a height H that is about 2.8% of the height of the trailer 10. The width W and the height H of the airflow supply duct 100 at both the first end 102 and the second end 104 may also be expressed as a ratio. The width to height (W/H) ratio at the first end 102 of the duct 100 may be in the range of about 1 to about 10. In one embodiment, the width to height (W/H) ratio at the first end 102 is about 6.7. The width to height (W/H) ratio at the second end 104 of the airflow supply duct 100 may be in the range of about 10 to about 20. In one embodiment, the width to height (W/H) ratio at the second end 104 is about 14. By increasing the width to height (W/H) ratio along the length L of the airflow supply duct 100, the second end 104 is oriented for tangential flow along the ceiling 12 of the trailer 10.
The airflow supply duct 100 includes an inlet portion 106 adjacent a first end 102, an outlet portion 110 adjacent a second end 104, and a central portion 108 disposed between the inlet portion 106 and the outlet portion 110. Both the inlet portion 106 and the outlet portion 108 are generally horizontal, such that when the airflow supply duct 100 is connected to the transport refrigeration unit 20, the inlet portion 106 and the outlet portion 110 are parallel to the top wall 12 of the trailer 10. In addition, the first end 102 and the second end 104 are arranged tangentially to the top wall 12 of the trailer 10. The central portion 108 of the airflow supply duct 100 is generally curved such that the plane of the inlet portion 106 is spaced a distance away from the plane of the outlet portion 110. In one embodiment, the curvilinear central portion 108 is generally S-shaped. In one embodiment, the contour of the central portion 108 is such that when the inlet portion 106 is positioned adjacent the opening 58 of the nozzle 56, a surface of the outlet portion 110 is in contact with the top wall 12 of the trailer 10.
In one embodiment, one or more splitter vanes 120 extend along at least a portion of the length L of the airflow supply duct 100 toward the second end 104 to separate the interior of the airflow supply duct 100 into multiple flow paths (
The airflow supply duct 100 includes a generally rectangular flange 140, adjacent the first end 102, for mounting the first end 102 near the opening 58 of the nozzle 56. The flange 140 may include a plurality of holes 142 such that fasteners may be used to couple the flange 140 to the evaporator section 40 of the transportation refrigeration unit 20 (see
The airflow supply duct 100 may be constructed from a plastic material, such as a medium density polyethylene for example. The inlet portion, outlet portion, and central portion of the airflow supply duct 100 may be formed integrally to give both the interior and the exterior of the airflow supply duct 100 a smooth contour. The airflow supply duct 100 may be constructed as a single piece, or alternatively, as a two piece assembly cut along the length L to form an upper portion and a lower portion. Manufacturing processes for the airflow supply duct 100 include, but are not limited to blow-molding, roto-molding, injection molding, thermoforming and or other similar processes.
The airflow supply duct 100 is more robust than the airflow chutes commonly used with transport refrigeration units 20. Because the airflow supply duct 100 has a thin profile that extends minimally from the ceiling of the trailer 10, the duct 100 occupies less space in the trailer 10 and is less susceptible to damage during loading and unloading. In addition, the shortened length of the duct 100, as well as its connection within the trailer 10 makes it easy to remove and clean. Inclusion of the airflow supply duct 100 also increases the reliability of the transport refrigeration unit 20. The duct 100 produces a strong, stable flow along the ceiling of the trailer 10, resulting in an improved flow distribution and uniformity of cargo temperature without restricting overall airflow. In addition, by improving the uniformity of the cargo temperature, the amount of time that the cargo may spend in the trailer 10 before its quality is compromised is increased.
While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US13/53892 | 8/7/2013 | WO | 00 |
| Number | Date | Country | |
|---|---|---|---|
| 61692066 | Aug 2012 | US |
