Abstract:
Disclosed is a serial fan which only occupies a small space, has a simplified assembling structure, and can effectively eliminate the interference between fans. The serial fan includes a main frame, a plurality of rotor vanes connected in series within the main frame along an axial direction of the serial fan, a first support disposed inside and connected with the main frame for supporting one of the plurality of rotor vanes, and a second support detachably connected with the first support for supporting another one of the plurality of rotor vanes.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention is related to a serial fan, and more particularly to an axial-flow fan with a plurality of rotor vanes connected in series in a single fan guard.  
         BACKGROUND OF THE INVENTION  
         [0002]    The axial-flow fan is a popular fan device which has the features of a simple structure, low cost, and a high airflow rate. Therefore, it has been widely used in various systems as an air conditioning or ventilating device, for instance, as a ventilation fan in a computer system.  
           [0003]    Generally, in order to avoid the interruption of operation due to the breakdown of fans, a set of standby fan system is usually provided and connected with the original fan system in series to prevent the system or device from being damaged. Moreover, because the total pressure of the axial-flow fan is relatively low, the axial-flow fan cannot fully develop a high airflow rate in a system of a high resistance. Thus, in the case that a high total pressure is needed, two or more axial-flow fans are connected in series to provide the high total pressure.  
           [0004]    Typically, a so-called serial fan is constituted by two independent fan units assembled through a specific circuit design. Each fan unit includes a fan guard and a rotor device. As shown in FIG. 1, the first fan unit is constructed by a fan guard  13  and a rotor device including a motor  11 , and a rotor vane  12  having a shaft ring  121  connected to the motor  11  and a plurality of blades  122  fixed on the circumferential surface of the shaft ring  121 . Likewise, the second fan unit is constructed by a fan guard  16  and a rotor device including a motor  14 , and a rotor vane  15  having a shaft ring  151  connected to the motor  14  and a plurality of blades  152  fixed on the circumferential surface of the shaft ring  151 . After the first and second fan units are assembled respectively, both of them are coupled together through screws (not shown), thereby completing the construction of the serial fan. However, such a design is more complicated and needs more time and manufacturing cost in the assembly of this serial fan.  
           [0005]    In fact, according to the above description, it can be found that the conventional serial fan is constructed by two independent fan units connected in series. However, the serial connection of two fan units can not guarantee that the total pressure of the airflow discharged from the fan can be doubled. Even if only one fan operates and the other still stays as a standby fan, the latter will reduce the total pressure in operation because the resistance between both of them is increased, thereby decreasing their operating efficiency. For example, when the airflow flows through these two fan guards  13 ,  16  having the structures as shown in FIG. 1 and as described, the airflow will encounter a plurality of ribs  131 ,  161 , thereby resulting in the generation of turbulent flows and an adverse effect on the blast pressure enhancement. Consequently, the heat-dissipating efficiency of the fan is reduced. Thus, in certain situations, the two axial-flow fans connected in series are separated far apart to minimize the interference between them. Nevertheless, this way can not be applied in the case that the space is limited.  
           [0006]    Therefore, it is desirable to develop an axial-flow serial fan with a plurality of rotor vanes that only occupies a small space, has a simplified structure, and can effectively eliminate the interference between two fans.  
         SUMMARY OF THE INVENTION  
         [0007]    An object of the present invention is to provide a serial fan which can be assembled easily, fastly and conveniently, and has a strengthened bonding structure.  
           [0008]    Another object of the present invention is to provide an axial-flow fan having a plurality of rotor vanes connected in series in a single fan guard, which can effectively eliminate the interference between fans.  
           [0009]    According to the present invention, the serial fan includes a main frame, a plurality of rotor vanes connected in series within the main frame along an axial direction of the serial fan, a first support disposed inside and connected with the main frame for supporting one of the plurality of rotor vanes, and a second support detachably connected with the first support for supporting another one of the plurality of rotor vanes.  
           [0010]    In accordance with one aspect of the present invention, the first support includes a first engaging member disposed on a base thereof and the second support includes a second engaging member disposed on a base thereof to be engaged with the first engaging member for tightly assembling the first support and the second support together. The first engaging member includes a plurality of retaining grooves formed on the base of the first support and the second engaging member includes a plurality of hook structures to be received by the plurality of retaining grooves, respectively. Certainly, the structure of the first engaging member can be exchanged with that of the second engaging member.  
           [0011]    In addition, the base of the first support has a flange and the base of the second support has an outwardly extended peripheral wall, the outer diameter of which is slightly smaller than the inner diameter of the flange of the first support such that the bases of the first and second supports are engaged with each other. Alternatively, the base of the second support has a flange and the base of the first support has an outwardly extended peripheral wall, the outer diameter of which is slightly smaller than the inner diameter of the flange of the second support such that the bases of the first and second supports are engaged with each other.  
           [0012]    In accordance with another aspect of the present invention, the serial fan further includes a plurality of motors respectively received by the first and second supports for driving the plurality of rotor vanes to rotate.  
           [0013]    Preferably, the serial first support has a base and a hollow cylinder substantially located at a center of the base for receiving one of the plurality of motors and the one of the plurality of rotor vanes. Likewise, the second support also has a hollow cylinder substantially located at a center of a base thereof for receiving another one of the plurality of motors and another one of the plurality of rotor vanes. The second support can be made of plastic or metal.  
           [0014]    In accordance with another aspect of the present invention, the first support is connected with the main frame through a plurality of guard blades radially arranged inside the main frame and fixed onto an inner surface of the main frame by each end thereof. Each of the plurality of guard blades has a shape substantially identical to that of each blade of the plurality of the rotor vanes for enhancing a heat-dissipating efficiency. Preferably, the first support, the main frame and the plurality of guard blades are integrally formed together and can be made of plastic and metal, respectively.  
           [0015]    In another preferred embodiment of the present invention, the serial fan further includes a separator for preventing a magnetic field interference between two adjacent motors. The separator can be disposed between one of the first and second supports and one of the plurality of motors, or between the first support and the second support, Preferably, the separator is a metal plate. More preferably, the separator is an adhesive tape containing a metallic component to be directly attached to a base of the first support or the second support.  
           [0016]    The present invention may best be understood through the following description with reference to the accompanying drawings, in which: 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0017]    [0017]FIG. 1 is an exploded diagram showing a conventional serial fan;  
         [0018]    [0018]FIG. 2 is an exploded diagram showing the first preferred embodiment of a serial fan according to the present invention;  
         [0019]    [0019]FIG. 3 a  is a top perspective view of a second support of the serial fan according to the present invention;  
         [0020]    [0020]FIG. 3 b  is a bottom perspective view of a second support of the serial fan according to the present invention;  
         [0021]    [0021]FIG. 4 a  is an elevation diagram of the first and second supports of the serial fan of the present invention before engaging with each other;  
         [0022]    [0022]FIG. 4 b  is a longitudinally sectionally amplified diagram of the part B in FIG. 4 a;    
         [0023]    [0023]FIG. 4 c  is an elevation diagram of the first and second supports of the serial fan of the present invention after engaging with each other;  
         [0024]    [0024]FIG. 4 d  is a longitudinally sectionally amplified diagram of the part B in FIG. 4 c;    
         [0025]    [0025]FIG. 4 e  is a longitudinally sectionally amplified diagram showing the assembly of the first and second supports, both of which have received a motor and a rotor vane thereon, respectively, taken along the line A-A in FIG. 4 a;    
         [0026]    [0026]FIG. 5 is an exploded diagram showing the second preferred embodiment of a serial fan according to the present invention; and  
         [0027]    [0027]FIG. 6 is a partially longitudinally sectionally amplified diagram showing the assembly of the separator and the first and second supports, the latter two of which have received a motor and a rotor vane thereon, respectively, along the axis of the serial fan. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0028]    The present invention will now be described more detailedly with reference to the following embodiments. It is to be noted that the following descriptions of the preferred embodiments of this invention are presented herein for the purpose of illustration and description only. It is not intended to be exhaustive or to be limited to the precise form disclosed.  
         [0029]    Please refer to FIG. 2 which is an exploded diagram showing the first preferred embodiment of a serial fan according to the present invention. The serial fan includes a main frame  21 , a first rotor vane  26 , a second rotor vane  28 , two motors  25 , 27 , a first support  22 , and a second support  24 . The first rotor vane  26  and the second rotor vane  28  have a plurality of blades formed around their outer side, respectively.  
         [0030]    The first support  22  is connected and fixed within the main frame  21  through a plurality of guard blades  23  which are radially arranged inside the main frame  21  and fixed onto an inner surface of the main frame  21  by each end thereof. Each of the plurality of guard blades has a shape substantially identical to that of each blade of the rotor vanes to increase the discharged airflow pressure of the fan for enhancing the heat-dissipating efficiency. The first support, the main frame and the plurality of guard blades can be integrally formed together and can be made of plastic, metal or a material other than plastic and metal for a desired purpose, respectively.  
         [0031]    The first support  22  has a base and a hollow cylinder  221  substantially located at a center of the base for receiving the first motor  25  and the first rotor vane  26  therein in sequence. The second support  24  also includes a base and a hollow cylinder  242  substantially located at a center of the base for receiving the second motor  27  and the second rotor vane  28  therein in order. The second support can be made of plastic, metal or a material other than plastic and metal for a desired purpose. In addition, the base of the second support further has a plurality of hook structures  241  as shown in FIG. 3 a  or FIG. 3 b,  and the base of the first support  22  has a plurality of retaining grooves  222  corresponding to the shape and position of the hook structures  241  as shown in FIG. 4 a  or FIG. 4 b.  When assembling the secomd support  24  with the first support  22  together, the second support  24  is rotated along the arrow direction shown in FIG. 4 a  so that the first sipport  22  and the second support  24  can be tightly combined together through the engagement between the retaining grooves  222  and the hook structures  241  as shown in FIG. 4 c  and  4   d.    
         [0032]    Additionally, the base of the first support  22  has a flange  223  and the base of the second support  24  has an outwardly extended peripheral wall  243 , the outer diameter of which is slightly smaller than the inner diagram of the flange  223  so that the bases of the first and second supports can be engaged with each other as shown in FIG. 4 e.  Thus, the combination of these two structures can further prevent the vibration on the direction perpendicular to the axial direction of the serial fan.  
         [0033]    When the motor  25  for driving the first rotor vane  26  to rotate and the first rotor vane  26  are received by the first support  22  in sequence and then the second support  24  is engaged with the first support  22  to receive the motor  27  for driving the second rotor vane  28  to rotate and the second rotor vane  28 , the assembly of the serial fan is completed and the first and second rotor vanes are connected in series within the main frame  21  along the axial direction of the serial fan.  
         [0034]    Because the second support  24  is detachably connected with the first support  22 , it is only necessary to telescope the base of the second support  24  onto the base of the first support  22  and rotate the second support  24  such that the first and second supports can be tightly combined together without needing any screws or other parts. Therefore, in comparison with the conventional serial fan, the serial fan of the present invention can be simply and fastly assembled and the cost of screws or other parts can be saved.  
         [0035]    Now, please refer to FIG. 5 which shows another preferred embodiment of the present invention. The structure of this serial fan is substantially identical to that of the above-mentioned structure except that the serial fan further includes a separator. Because the distance between these two motors  35 ,  37  and that between the magnets (not shown) are relatively short after all components are assembled together, a separator  39  is disposed between these two motors  35 ,  37  for preventing a magnetic field interference between two adjacent motors.  
         [0036]    The separator  39  can be disposed between the first support  32  and the motor  35 , between the second support  34  and the motor  37 , or between the first support  32  and the second support  34 . The separator can be made of any material with the function of isolating the magnetic field. Preferably, the separator is a metal plate. More preferably, the separator is an adhesive tape containing a metallic component, which can be cut into the shape and size substantially identical to the base of the first or second support to be directly attached to the base of the first support or the base of the second support (on the side of the support with the hollow cylinder or the opposite side facing the base of the other support). Please refer to FIG. 6 which shows the relative position of each component after the first support  32  receives the separator  39 , the motor  35 , and the first rotor vane  36  thereon and the second support  34  receives the motor  37  and the second rotor vane  38  thereon.  
         [0037]    Certainly, the rotation speed, the rotation direction, the number of blades, and the tilting angles of blades of the first rotor vane can be identical to or different from those of the second rotor vane. These can be adjusted according to the actual requirement and application to attain the purpose of further enhancing the heat-dissipating efficiency of the serial fan. In addition, the structures of the first and second supports can be exchanged to achieve the same effect.  
         [0038]    In conclusion, the present invention provides a serial fan which can be assembled easily, fastly and conveniently, and has a strengthened bonding structure. Not only can it save the cost of screws or other parts but reduce the assembling time. Additionally, in order to prevent the magnetic field interference between two adjacent motors resulting from too close between the two motors, the present invention further provides a separator to be disposed between two motors for effectively elminating the magnetic field interference. Moreover, the present invention provides an axial-flow fan having a plurality of rotor vanes connected in series in a single fan guard (or main frame), and a plurality of guard blades radially arranged inside the main frame and fixed onto an inner surface of the main frame by each end thereof for connecting and fixing the first support  22  within the main frame  21 , wherein each guard blade has a shape substantially identical to that of each of the rotor vanes, which can contribute to an increase in the discharged airflow pressure of the fan for enhancing its heat-dissipating efficiency.  
         [0039]    While the invention has been described in terms of what are presently considered to be the most practical and preferred embodiments, it is to be understood that the invention need not be limited to the disclosed embodiment. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures.