1. Field of the Invention
The present invention relates to a cool air circulation apparatus in a refrigerator. More specifically, the invention relates to a cool air circulation apparatus in a refrigerator having an upper curved lip formed at a front face of a lower shelf, by which the cool air contacting with ambient air is discharged outside of the refrigerator and only the cool air adjacent to a refrigerating chamber flows into the refrigerating chamber.
2. Prior Art
A conventional refrigerator is illustrated in FIG. 1 and FIG. 2, which comprises a freezing chamber 1 and a refrigerating chamber 2. A compressor 10 is mounted on a rear lower portion of the refrigerator, and an evaporator 20 is provided at a rear portion of the freezing chamber 2. A refrigerant is compressed by operation of the compressor 10, and the compressed refrigerant flows toward the evaporator 20, thereby cooling the circulating air by the evaporation of the refrigerant.
Fans 23, 24 for circulating cool air are provided at the rear portion of the freezing chamber 1, and the air cooled through the evaporator 20 is supplied to the freezing chamber 1 and the refrigerating chamber 2 via each cool air duct which will be illustrated later.
The cool air duct 25 is provided in a rear portion of the freezing chamber 1, and the cool air forcedly enters into the cool air duct 25 by the operation of the fan 23, and further enters into the freezing chamber 1 through a plurality of openings 27 formed at a duct cover 25C provided between the freezing chamber 1 and the evaporator 20.
Another cool air duct 26 is formed behind the cool air duct 25 opposite to the freezing chamber 1. The duct 26 is branched in two passages 26A, 26B, preferably, and each passage is further extended down along each rear side of the refrigerating chamber 2. The cool air forcedly enters into each passage 26A, 26B by the operation of another fan 24, and further enters into the refrigerating chamber 2 through a plurality of openings 28 formed at a duct cover 26C. Preferably, other openings 29 channeled from corresponding passages 26A, 26B are provided at each inner side wall of the refrigerating chamber 2.
A cool air supply duct 42 is arranged under a partition wall 41 divided from the freezing chamber 1 and the refrigerating chamber 2, which extends from the rear portion of the refrigerating chamber 2 to the front portion of the refrigerating chamber 2. A chamber 42a for housing an air curtain fan 44 is formed at one end of the duct 42 proximal to the rear portion of the refrigerating chamber 2, and an air discharge opening 43 is formed at another end of the duct 42 opposite to the chamber 42a. The air discharge opening 43 is preferably formed along the entire width of the upper portion of an accessible opening 2C of the refrigerating chamber 2.
The fan 44 for generating the air curtain stream is housed in the chamber 42a, thereby enabling the air to flow smoothly. Preferably, the length of the fan 44 corresponds to the inner width of the chamber 42a, and is operated by additional motor 46.
Since the upper surface of the duct 42 is flatly extended, and the lower surface of the duct 42 is sloped up to the air discharge opening 43, the cross-section area of the duct 42 is decreased more and more toward the opening 43. The velocity of the cool air flowing along near the upper inner surface of the air duct 42 is faster than that of the air along the lower inner surface of the air duct 42. A front end of the bent discharge opening 43 of the duct 42 is straight which causes the discharging cool air to flow straight.
An air collecting duct 47 is extended down a long a rear center portion of the refrigerating chamber 2, and plural air collecting openings 48, 48A, 48B channeled from the air collecting duct 47 are formed at a duct cover 47C.
The refrigerating chamber 2 is divided by plural shelves 49, 49A, 49B, the upper surface of which is preferably flat-shaped to enhance effective air collection. A cross-section area of the opening 48 formed at the uppermost area of the refrigerating chamber 2 is smaller than that of the opening 48A formed at the middle height area of the refrigerating chamber 2, and a cross-section area of the opening 48A is smaller than that of the opening 48B formed at the lower height area of the refrigerating chamber 2. Height of each opening 48, 48A, 48B is determined according to volume of storage foodstuffs, but each opening 48, 48A, 48B is preferably formed at approximately halfway up each shelf 48, 48A, 48B. Further, each opening 48, 48A, 48B has a rectangular shape having a long longitudinal side or an oval shape.
The operation of the refrigerator configurated above is illustrated as follows. When a door (not shown) is opened, the fan 44 commences operation, and simultaneously the fan 24 terminates operation. The cool air is discharged through the opening 43 by the operation of the fan 44, thus forming the cool air curtain. The cool air circulating in the refrigerating chamber 2 does not escapes from the refrigerating chamber 2, thereby maintaining a constant temperature of the refrigerating chamber 2.
However, even if the cool air discharged from the opening 43 has the same low temperature between the distal layer and the proximal layer to the refrigerating chamber, the temperature of the distal layer of the air curtain increases greatly while the air stream flows downward in contact with ambient temperature air. Therefore, the air curtain flow has high temperature and the air enters into the refrigerating chamber. The high temperature air further flows into each air collecting opening, and recirculates in the refrigerating chamber. Thus, there is a problem in that the temperature of the refrigerating chamber increases, causing a decline in the cooling efficiency of the refrigerator.