Patent Publication Number: US-6210114-B1

Title: Cross flow fan for air conditioner

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a fan, and more particularly to a cross flow fan for an air conditioner. 
     2. Description of the Prior Art 
     Generally, an indoor unit in a separable air conditioner is constructed to occupy as small a space as possible and to generate as much wind as possible and the indoor unit is generally disposed with a horizontally formed cross flow fan. 
     The cross flow fan is disposed, as illustrated in FIG. 7, with a plurality of horizontal blades  51  mounted on a plurality of diaphragms  50 , each arranged at a predetermined interval, and a rotary axle  52  piercing the plurality of diaphragms  50  and protruding at both ends of the diaphragms  50 . 
     In other words, as illustrated in FIG. 8 blades  51 , each having a predetermined length, are coupled to the diaphragms  50  where coupling holes  53  are sequentially arranged to insert the blades thereinto, to form a partitioning fan  54  and to stack the partitioning fans  54  by way of ultrasonic fusion for formation of a cross flow fan. 
     The purpose of partially forming the cross flow fan by way of the plurality of diaphragms  50  is to prevent deflection or deformation of the blades  51  as the blades  51  are made of relatively thin material. 
     SUMMARY OF THE INVENTION 
     However, there is a problem in the cross flow fan thus constructed in that fluid flowing in the fan is curtailed in flowing freely and energy efficiency is reduced due to weight increased by the cross flow fan having a plurality of diaphragms when the plurality of diaphragms are mounted to form a plurality of partitioned fans when the cross flow fan is manufactured. 
     There is another problem in that amount of wind output from the fans is reduced when the fluid is impeded in flowing freely. 
     The present invention is disclosed to solve the aforementioned problems and it is an object of the present invention to provide a cross flow fan for an air conditioner adapted to increase a free flow of fluid flowing in the fan, thereby increasing an amount of wind from the fan and improving an energy consumption efficiency. 
     In accordance with the object of the present invention, there is provided a cross flow fan for an air conditioner constructed to allow a plurality of horizontally and sequentially arranged blades to be partitioned, each distanced by a predetermined space, by a plurality of vertically arranged diaphragms, wherein the cross flow fan comprises a through hole so formed as to have a diameter of 0.4˜0.8D against a diameter D of the diaphragm, such that fluid infused into the fan can form an eddy current. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For fuller understanding of the nature and objects of the invention, reference should be made to the following detailed description taken in conjunction with the accompanying drawings in which: 
     FIG. 1 is a perspective view for illustrating a diaphragm arrangement status of a cross flow fan for an air conditioner according to the present invention; 
     FIG. 2 is a side sectional view of a diaphragm in FIG. 1; 
     FIG. 3 is a side sectional view of a central diaphragm in FIG. 1; 
     FIG. 4 is a graph for illustrating a stress and a required stress change according to diameter of a through hole formed at a diaphragm in FIG. 1; 
     FIG. 5 is a graph for illustrating a volume efficiency change according to length of guide vane formed at a central diaphragm in FIG. 1; 
     FIG. 6 is a graph for illustrating a fluid amount ratio between rpm of a cross flow fan according to the present invention and a cross flow fan according to the prior art; 
     FIG. 7 is a perspective view for illustrating a cross flow fan for an air conditioner according to the prior art; and 
     FIG. 8 is an exploded perspective view of a diaphragm. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     As illustrated in FIGS. 1,  2  and  3 , the diaphragm  50  is formed with a through hole  1  having a diameter of 0.78D against a diameter (D) of the diaphragm  50  for easy flow of the fluid. The reason of limiting the diameter of the through hole  1  at 0.78D is that, as illustrated in FIG. 4, eddy current is maximally generated when strength at a place where a blade  51  is coupled is optimally maintained. 
     In FIG. 4, the vertical axis represents a stress ratio on the diaphragm  50  against a stress required for strength guarantee and the longitudinal axis defines a ratio between the diameter of the through hole  1  and the diameter D of the diaphragm  50 , where it should be noted that the same effect may be of attained if the ratio between the diameter of the through hole  1  and the diameter of the diaphragm  50  is 0.4—0.8D. 
     Particularly, the diaphragm  50  is centrally formed with a central diaphragm  2  for improving a fluid volume efficiency in a fan. The central diaphragm  2  is formed to increase a volume efficiency as the eddy current is increased in its formation in the fan. In other words, the central diaphragm  2  is disposed at radial lines with guide vanes  3 , and length of each guide vanes  3  is formed at 0.23D, where D is a diameter of the central diaphragm  2 . The eddy current is increased in amount thereof by blowing action or eddy current forming action of the guide vanes  3  from center of the fan to both sides thereof. 
     Furthermore, a sectional area of the guide vane  3  has a shape of an air foil, such that, when a fan is rotated, eddy current is maximally formed by the guide vanes  3  but frictional loss is minimized. The guide vane  3  is formed to have a gradually increasing incline of approximately 4.07% as they go from the center of the central diaphragm to periphery thereof. Although the guide vane  3  produces an optimal efficiency at a length of 0.23D, it can obtain a good voluminal efficiency at a range of 180˜0.5D. 
     In other words, if the length of the guide vane  3  is within a range of 0.2˜0.5D, the voluminal efficiency can be maintained at a good level. 
     Now, operational efficiency of the cross flow fan according to the present invention will be described. 
     When a power is applied to an air conditioner, the cross flow fan is rotated to suck the room air. The sucked room air flows in the fan through the through hole  1  formed at the diaphragm to generate an eddy current, where fluid sucked into the fan forms stronger eddy current according to the guide vanes  3  formed at the central diaphragm  2 . 
     In other words, the guide vanes  3  make the fluid in the fan a horizontal eddy current to thereby increase a voluminal efficiency of the fluid sucked into the fan. The ratio of fluid amount is improved by approximately 165% compared with a conventional fan when a rated revolution is given at 1,600 rpm, as illustrated in FIG.  6 . Of course, even if the revolution is dropped to 500 rpm, amount of fluid is improved by approximately 130% compared with the conventional fan, such that it can be noted that amount of wind blown by the cross flow fan according to the present invention has been markedly increased. 
     Particularly, in case the same amount of blown wind is maintained as that of the conventional fan, it is all right to have a low rpm of the cross flow fan according to the present invention, such that a starting power is reduced by approximately 19% at a predetermined amount of wind output. 
     Furthermore, because the central diaphragm  2  is formed with guide vanes  3 , not with through hole  1 , it is heavier than other diaphragm  50 , such that it functions as a fly wheel when the cross flow fan is rotated to further stabilize a rated rotation of the cross flow fan. 
     As apparent from the foregoing, there is an advantage in the cross flow fan according to the present invention in that the diaphragm of the cross flow fan is formed with a through hole of 0.78D and a central diaphragm having guide vanes, each having a diameter of 0.23D, such that amount of blown wind from the cross flow fan is increased to thereby reduce a starting power.