Patent Publication Number: US-2006013712-A1

Title: Wet and dry pump

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to a wet and dry pump, and particularly, to a wet and dry pump capable of making wet air or liquid pass through a space between a stator and a rotor by processing a motor to be damp-proof.  
      2. Description of the Conventional Art  
      As shown in  FIGS. 1 and 2 , a conventional wet and dry pump includes: a housing  110  provided with a cylindrical impeller cover  111  and a cylindrical motor cover  112 ; an impeller  120  rotatably installed in the impeller cover  112 ; a motor  140  installed in the motor cover  112  and connected to the impeller  120  and a rotating shaft  130 , for providing a driving force to rotate the impeller  120 ; and a cooling fan  170  connected to the rotating shaft  130  and rotated by a rotation of the rotating shaft  130  and thereby sucking a cooling air into the motor cover  102  to discharge it.  
      An inlet  113  for sucking fluid by an operation of the impeller  120  is formed at a central upper portion of the impeller cover  111 , and a plurality of outlets  114  for discharging the fluid flowed in the impeller cover  111  is formed at a circumference of the impeller cover  111 .  
      A suction opening  115  for sucking cooling air by an operation of the cooling fan  170  is formed at a central lower portion of the motor cover  112 , and a plurality of discharge openings  116  for discharging the air having performed a cooling operation to the outside are formed at a circumference of the motor cover  112 .  
      The motor  140  includes: a stator  141  of a ring shape fixed at an inner circumferential surface of the motor cover  112 ; and a cylindrical rotor  142  fixed at an outer circumference of the rotating shaft  130 , maintaining a certain gap with an inner circumferential surface of the stator  141 . According to this, the air sucked by the cooling fan  170  discharges to the outside a heat generated from the motor  140  when the air passes through the gap between the stator  141  and the rotor  142 .  
      A shielding wall  117  is installed between the impeller cover  111  and the motor cover  112 . As a result, the fluid sucked by the impeller  120  can not be flowed in the motor cover  112  and the cooling air sucked by the cooling fan  170  can not be flowed in the impeller cover  111  as well.  
      According to the aforementioned construction, when the motor  140  is operated, the impeller  120  is rotated by the rotation of the rotating shaft  130 . As a result, fluid is flowed in the impeller cover  111  through the inlet  113  of the impeller cover  111  and discharged to the outside through the outlet  114 .  
      Additionally, once the cooling fan  170  is rotated by the rotation of the rotating shaft  130 , the external air is sucked in the motor cover  112  through the suction opening  115  and cools the motor  140  while passing through the gap between the stator  141  and the rotor  142 , thereafter being discharged to the outside through the discharge opening  116 .  
      In the aforementioned conventional wet and dry pump, since the shielding wall  117  for shielding a space between an inner space of the impeller cover  111  and an inner space of the motor cover  112  is installed therein, the fluid flowed in the impeller cover  111  is prevented from being flowed toward the motor  140  and thereby the conventional wet and dry pump can pump wet air or liquid.  
      However, because the conventional wet and dry pump should have the cooling fan  170  for cooling the motor  140 , power loss of approximately 60˜70W is occurred, and noise of approximately 2˜3 dB is disadvantageously increased thereby.  
     SUMMARY OF THE INVENTION  
      Therefore, an object of the present invention is to provide a wet and dry pump capable of improving a cooling efficiency of a motor by processing it to be damp-proof and thus by making wet air or liquid pass through a space between a stator and a rotor, and capable of improving characteristics of power consumption and noise by removing a separate cooling fan for cooling the motor.  
      To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, there is provided a wet and dry pump, comprising: a housing having an inlet and an outlet of fluid; an impeller rotatably disposed in the housing; and a motor including a rotating shaft connected to the impeller, a stator fixed to an inner circumferential surface of the housing and having a damp-proof-processed winding coil therein, and a rotor fixed to an outer circumference of the rotating shaft with maintaining a certain gap with an inner circumference of the stator.  
      The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention.  
      In the drawings:  
       FIG. 1  is a front view showing a conventional wet and dry pump;  
       FIG. 2  is a longitudinal sectional view showing the wet and dry pump shown in  FIG. 1 ;  
       FIG. 3  is a front view showing a wet and dry pump according to the present invention;  
       FIG. 4  is a longitudinal sectional view showing the wet and dry pump shown in  FIG. 3 ;  
       FIG. 5  is a perspective view showing a partially cut stator in  FIG. 3 ;  
       FIG. 6  is a graph showing respective power consumption of the wet and dry pump according to the present invention and that of the conventional wet and dry pump, respectively in comparison therewith; and  
       FIG. 7  is a graph showing respective operation noise of the wet and dry pump according to the present invention and that of the conventional wet and dry pump in comparison therewith. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings.  
      Referring to  FIGS. 3 and 4 , a wet and dry pump according to the present invention is comprised of: a housing  10  provided with a cylindrical impeller cover  11  having an inlet  13  at a central upper portion thereof and a cylindrical motor cover  12  having a plurality of outlets  14  and  15  along an outer circumference thereof; an impeller  10  rotatably installed in the impeller cover  11 ; and a motor  40  installed in the motor cover  12  and connected to the impeller  20  and a rotating shaft  30 , for providing a driving force to rotate the impeller  20 .  
      The motor  40  includes: a stator  41  of a ring shape fixed to an inner circumferential surface of the motor cover  12 ; and a rotor  42  fixed to an outer circumference of the rotating shaft  30 , maintaining a certain gap  50  with an inner circumference of the stator  41 .  
      A brushless motor, particularly, a switched reluctance (SRM) motor is preferably applied as the motor  40 , and according to characteristics of the brushless motor, the rotor  42  has a characteristic of damp-proofing.  
      As can be seen from  FIG. 5 , the stator  41  is comprised of: a plurality of bobbins  46  arranged as a ring shape and the each bobbin having a coil  45  which is wound therein, wherein entire outer portion of the each bobbin is molded ( 43 ) with a material such as a synthetic resin; and a plurality of conductors  47  connected to the plurality of bobbins  46 , respectively, and exposed to the outside of the molding portion  43  at a certain interval along an inner circumference of the stator  41 . As a result, even although wet air or liquid passes through a space between the stator  41  and the rotor  42 , the coils  45  in the molding portion  43  are shielded from the wet air or the liquid.  
      The molding portion  43  has a plurality of protruded portions  48  and recessed portions  49  along an outer circumference thereof in order to form a cooling passage  51  through which fluid sucked by the impeller  10  passes for cooling the motor  40 . Namely, the protruded portion  48  of the molding portion  43  is fixed to an inner circumferential surface of the motor cover  12  via welding or other engaging means, thus the cooling passage  51  is formed between the recessed portion  49  of the molding portion  43  and the inner circumferential surface of the motor cover  12 .  
      The plurality of outlets  14  and  15  formed at the motor cover  12  are comprised of: a first outlet  14  formed at an upper side of the stator  41 , for first discharging the fluid flowed in from the impeller cover  11 ; and a second outlet  15  formed at a lower side of the stator  41 , for passing fluid, which is not discharged to the outside through the first outlet  14 , through the space between the stator  41  and the rotor  42  and thereafter for discharging to the outside.  
      The rotating shaft  30  can be protruded to the outside of the motor cover  12 . In this case, a bearing  17  is preferably installed between the rotating shaft  30  and the motor cover  12 .  
      Preferably, a guide member  22  for guiding the fluid flowed in by the impeller  20  toward the motor cover  12  is installed between the impeller cover  11  and the motor cover  12 . In the embodiment of the present invention, the guide member  22  has a flat type of ring shape forming a curved surface toward the impeller  20 .  
      Hereinafter, an operation of the wet and dry pump according to the present invention will be described.  
      First, once the rotor  42  is rotated by an electromagnetic interaction between the stator  41  and the rotor  42 , the impeller  20  connected to the rotor  42  and the rotating shaft  30  is rotated and thereby external fluid is flowed in through the inlet  13  of the impeller cover  11 .  
      The fluid flowed in the impeller cover  11  is guided to the guide member  22  to be flowed in the motor cover  12 . A part of the fluid flowed in the motor cover  12  is discharged to the outside through the first outlet  14 , and non-discharged fluid passes through the cooling passage  50  between the stator  41  and the rotor  42  as well as the cooling passage  51  between the inner circumference of the motor cover  12  and the outer circumference of the stator  41  in order to cool the motor  40 . Furthermore, the fluid having performed the cooling operation for the motor  40  is discharged to the outside through the second outlet  15 .  
      Hereinafter, effect of the wet and dry pump in accordance with the present invention will be explained with reference to  FIGS. 6 and 7 .  
       FIG. 6  is a graph showing a variation of power consumption based on a diameter of the inlet  13 , namely, variation of suction capacity of the pump according to the present invention with the conventional pump, respectively. As shown in  FIG. 6 , it can be noticed that the pump according to the present invention consumes power less than the conventional pump does because the cooling fan for cooling the motor has been removed.  
       FIG. 7  is a graph showing noise measured in the conventional pump and the pump according to the present invention, respectively. As shown in  FIG. 7 , it can be noticed that the pump according to the present invention is improved characteristics of noise in comparison with the conventional pump because the cooling fan for cooling the motor has been removed.  
      As stated above, the wet and dry pump according to the present invention can advantageously improve a cooling efficiency of the motor by processing it to be damp-proof and then making wet air or liquid pass through a passage between the stator and the rotor.  
      Furthermore, the wet and dry pump according to the present invention can efficiently improve characteristics of power consumption and noise by removing the cooling fan for cooling the motor.  
      As the present invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be construed broadly within its spirit and scope as defined in the appended claims, and therefore all changes and modifications that fall within the metes and bounds of the claims, or equivalence of such metes and bounds are therefore intended to be embraced by the appended claims.