Prior art refrigerators typically introduce cold air at the top of a cabinet through a cold-air supply duct. They also typically draw in or “intake” warm air at the bottom of the cabinet through a “return” air duct. Locating a cold air supply duct at the top of a refrigerator cabinet takes advantage of the fact that cold air, being denser that warm air, falls downwardly, however, in some instances, locating the cold air supply duct at the top of a refrigerated cabinet can provide a less than optimum air flow distribution. The temperature inside the refrigerator at different elevations and different horizontal locations can be uneven if the refrigerated air introduced at the top of a cabinet is able to find an unobstructed path to the warm air return.
The refrigerator 100 has an interior space or volume 200 defined by the left side 106 and the right side 108 (shown in
Still referring to
Air drawn through the evaporator 216 by the fan 218 is also forced by the fan 218 through the curving connecting portion 214 and into the second, vertical portion 212. The refrigerated air, identified by reference numeral 220, is forced downwardly toward the bottom 104 of the refrigerator 100. When the refrigerated air 220 reaches the bottom 104 of the second portion 212 of the duct 206, the air is forced into a converging duct portion 230 defined by an inclined and perforated screen 232. As described more fully below, air that is below the perforated screen 232 is at a pressure that is elevated, i.e., higher than, the pressure of the air above the screen 232.
The perforated inclined screen 232, which is also referred to interchangeably hereinafter as the screen 232, the inclined screen 232 and the perforated screen 232, has a downwardly-directed bend or inflection point 234 located near the door 110 whereat the perforated screen is directed to the bottom 104 of the refrigerator 100. The bend 234 extends across the width of the screen 232, which extends into the plane of
The inclined screen 232 has a rear edge 238 abutting and attached to the front panel 240 of the second portion 212 of the duct 206. The rear edge 238 also extends across the width of the screen 232. Since the front panel 240 of the second portion 212 of the duct 206 is effectively the rear or back side of the refrigerated air space, the front panel 240 is considered to be a rear side of the refrigerator to which the incline screen 232 is attached at its rear edge 238.
The inclined screen 232 is perforated with numerous holes 242. Air 220 that is forced down the second duct portion 212 enters the space below the screen 232. Since air continues to flow through the screen 232, the screen 232 is considered to act as a duct. Since the screen 232 is inclined at an inclination angle 250 as shown, and which is measure relative to the bottom 104 of the refrigerator 100, the screen 232 defines a converging air duct 244.
Cold air 220 exits the second portion 212 of the duct 206 at a relatively tall opening 213 having a height 246. The height 245 of the opening 254 is defined by the elevation of the rear edge 238 above the bottom 104 of the refrigerator 100. The screen 232, being inclined at an angle 250 relative to the bottom 104 converges or gets closer to the bottom 104 as the screen length extends toward the front 110 of the refrigerator 100. The inclination point or front edge 234 of the screen 232 is thus much closer to the bottom 104 than is the rear edge 238 of the screen. The converging duct portion 244 is thus considered to have an opening 254, into which cold air 220 from the second portion 212 of the duct 206 flows, responsive to the fan 218. In
The inclined screen 232 can be seen to extend all across the interior 200 of the refrigerator to meet and make contact with both the left side 106 and the right side 108. The front 110 can be seen to be a door 110, which is attached to the top 102 and the bottom 104 by hinges 300 that are attached at the right side 108 of the refrigerator. A handle 302 enables the door 110 to be opened and closed. A glass panel 304 in the door 110 allows the interior of the refrigerator to be viewed without opening the door.
As
The inclined screen 232 has a top surface 312 and a bottom surface 314. The holes 242 extend through the top and bottom surfaces 312 and 314 respectively. Air flows through the holes 242 by virtue of the fact that the air pressure inside the converging duct portion 244, below the screen 232 and its lower or bottom surface 314, is greater than or “elevated” relative to the pressure in the interior portion 200 of the refrigerator 100, i.e., above the top surface 312. Stated another way, a fan that draws air into the warm air inlet 306 and pressurizes the portion of the duct 206 that is downstream from the fan, also pressurizes the converging duct portion 244. The converging duct portion 244 and the inclined screen 232 thus define a pressurized air plenum. If the pressure drop across the screen 232, i.e., the pressure below the screen 232 minus the pressure above the screen, is substantially uniform across the area of the screen 232, the volumetric flow rate of air through each of the openings 242 through the screen 232 will also be substantially uniform. On the other hand, if the air pressure drop across the screen is not uniform, air flow through some of the holes 242 will be greater than or less than air flow through others holes 242. The pressure drop across the screen is kept relatively uniform across the lower surface 314 of the screen 232 by selecting one or more of: the fan's air flow rate; dimensions of the duct 206, including its various portions; the area of the screen 232; the inclination angle 250 of the screen 232; the number of holes 242; the open area of the holes 242 and the thickness of the material from which the screen 232 is made,
As used herein, a completely uniform flow rate or nearly uniform flow rate through the holes 242 in the screen 232, is considered herein to be a uniform air flow profile. In
Referring again to
The screen 702 has a width 704 less than the width 706 of the interior 708. The rear edge 710 meets or abuts with the rear surface 712 of a rear duct 714. The width 704 being less than the width 706 provides open spaces 716 beyond the left edge 718 and the right edge 720 of the screen 702. The open spaces 716 are considered herein to be themselves openings within a perimeter region 722 that is located beyond the extreme edges 718 and 720 of the screen 702. The perimeter 722 is located beyond the edges 718 and 720. The fact that there is no screen between the edges 718 and 720 and the left side 730 and the right side 732 means that air is able to freely flow upward through those openings providing an increased air flow there through.
Those of ordinary skill in the art will recognize that while the openings in the screens depicted and described above are substantially uniform, as well as being evenly spaced, alternate embodiments include the use of holes through a screen that are neither equal nor evenly distributed. Stated another way, in a preferred embodiment the thickness of the screen, its area, its extent between the left and right sides, the number of openings, the inclination angle of the screen are selected or configured to provide a uniform distribution of air flow through the screen across its area or substantially across the area. In one alternate embodiment, at least one of the thickness, the area and number of openings and the inclination angle are configured to provide a non-uniform air flow distribution. In one such alternate embodiment, at least one of the thickness, area and number of openings and the inclination angle are each configured to provide an increased air flow through at least some of the openings that are near at least one of the left edge of the screen, the right edge of the screen or the front edge in order to provide an increased air flow through such openings. The increased air flow through such openings is relative to an average air flow through at least a central region of the inclined screen portion.
In yet another alternate embodiment, at least one of the thickness, area, number of openings, inclination angle and the dimensions of the screen inclined portion between the front edge and the rear edge are selected to provide an increased air flow through openings in a region considered to be a perimeter that is around the exterior edges of the screen.
Those of ordinary skill in the art will recognize that the portion of the screen that is beyond the front edge (identified by “234” in the embodiment shown in
For purposes of clarity, it is important to note that the converging duct portion is considered to have an inlet. The inlet is considered to be at least a geometric plane extending downwardly from the rear edge (“238” in the embodiment shown in
In a preferred embodiment, which is shown in
The foregoing description is for purposes of illustration. The true scope of the invention is set forth in the following claims.