Patent Document

BACKGROUND OF THE PRESENT INVENTION 
       [0001]    1. Field of Invention 
         [0002]    The present invention relates to a gas-water mixing pump, and more particularly to a small gas-water mixing pump used for mixing ozone and water, wherein the motor has an output power less than 50 W. 
         [0003]    2. Description of Related Arts 
         [0004]    Ozone is an excellent chemical preparation, because it can instantly kill bacteria and viruses. It can also decompose harmful chemical pollutant without creating new pollutants. Therefore, the ozone has been widely applied to large scale water treatment equipment. The household appliances, such as dish washers and washing machines have been widely used, and need to be treated by ozone. However, ozone has not been practically applied to the household appliances. The main reason that ozone has not been applied to the household appliances is that small ozone gas-water mixing equipment, which is efficient, stable and low cost, is not available yet. 
         [0005]    High ozone concentration in the air is harmful to human beings. Therefore, the dissolving efficiency of the ozone gas-water mixing equipment should be high, so as to limit the ozone concentration to environmental standards. The mixing pump has high dissolving efficiency, so it is adopted in industry. However, industrial mixing equipment is not applicable to household appliances. 
       SUMMARY OF THE PRESENT INVENTION 
       [0006]    An object of the present invention is to provide a small ozone gas-water mixing pump (having a motor output power less than 50 W), which is applicable to the household appliances, such as dish washers and washing machines, etc. 
         [0007]    Another object of the present invention is to provide a small ozone gas-water mixing pump (having a motor output power less than 50 W), which is highly efficient, stable, reliable, small in size, and low cost. 
         [0008]    The principle of the present invention is that the rotation of the leaves of the water pump produces intense turbulence vortex, and the bubbles in the water are torn up to produce more and smaller bubbles, so that the ozone is efficiently mixed with and dissolved into water. Accordingly, in order to accomplish the above object, the present invention provides a pump casing, an impeller, and a motor. A permanent magnet A is provided on the impeller. Outside of the pump casing, at a place corresponding to the permanent magnet A, a permanent magnet B is mounted on a device connected to the rotor of the motor, like a rotary plate connected with or integrated with the rotor. The motor drives the permanent magnet B to rotate. According to the character of magnetic poles, that is unlike poles attract and like poles repel, the permanent magnet B pushes the permanent magnet A to rotate through magnetic force, so as to drive the impeller to rotate synchronously. Thus, the motor drives impeller without shafting. 
         [0009]    Ozone is strong oxidant, which can accelerate the aging of the sealing rubber, so that using rubber gasket to seal driving shaft for a water pump is not reliable, especially when there is ozone in water, and this problem has been existed for a long time. The ceramic seal ring widely adopted by the present water pump is more reliable than the rubber gasket, but has a complicated structure, costs a lot, and takes up more room; besides, it still partially uses rubber gasket. For tiny or small pump, shaft sealing produces higher frictional resistance, which consumes a large part of the motor output power. The frictional resistance of the same kind of product cannot be assured to be the same. In this case, the output power of the water pump of the same kind of product significantly varies. Therefore, for household appliance, the water pump with a driving shaft cannot be adopted. 
         [0010]    The present invention uses magnetic force to drive impeller without using a driving shaft, so that the driving shaft sealing problems is avoided, and the maintenance work is easier. The driving structure using magnetic force is simple in structure. If the brushless DC motor is adopted, the permanent magnet B is mounted on the rotary plate of the motor rotor. This structure is safe, simple, and small, so as to be applied to the tiny or small pumps. Without using shaft, the coaxial precision demand between the impeller and the motor shaft is lowered, and the motor and the pump body is easily maintained and replaced. If the impeller is trapped or overloaded, the motor will not be trapped or overloaded, so as to avoid the burning damage of the motor. 
         [0011]    These and other objectives, features, and advantages of the present invention will become apparent in the following detailed description, the accompanying drawings, and the appended claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0012]      FIG. 1  is a schematic view of a centrifugal type mixing pump according to the preferred embodiment of the present invention. 
           [0013]      FIG. 2  is a schematic view of a vortex type mixing pump according to the above preferred embodiment of the present invention. 
           [0014]      FIG. 3  is a schematic view of a vortex type mixing pump according to the above preferred embodiment of the present invention, illustrating the ozone conduit and the water flowing direction. 
           [0015]      FIG. 4  is a schematic view of a vortex type mixing pump according to the above preferred embodiment of the present invention, illustrating an application of a brushless DC motor. 
           [0016]      FIG. 5  is a side sectional view of a vortex type mixing pump according to the above preferred embodiment of the present invention. 
           [0017]      FIG. 6  is a top sectional view at plane A-A of a vortex type mixing pump according to the above preferred embodiment of the present invention. 
           [0018]      FIG. 7  is a side sectional view of a vortex type mixing pump having only one water channel according to the above preferred embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0019]    Referring to  FIG. 1  of the drawings, a structure of a centrifugal type mixing pump according to a preferred embodiment of the present invention is illustrated. A water inlet is provided on the central axis of the mixing pump. Leaves  3  are provided on the surface of an impeller  2 . A permanent magnet A ( 4 ) is provided on an outer circle portion of the impeller  2 . Outside of the pump casing  1 , at a place corresponding to the permanent magnet A ( 4 ), a permanent magnet B ( 5 ) is mounted on a device coaxially connected with the motor  6 , such as a rotary plate. The motor  6  drives the permanent magnet B ( 5 ) to rotate, and the permanent magnet B ( 5 ) impulses the permanent magnet A ( 4 ), so as to drive the impeller  2  to rotate synchronously. The rotating leaf  3  drives water to rotate, produces centrifugal force, and increases the pressure and moving speed of the water. The speedy leaves  3  interact with the stationary pump casing  1  to produce an intense turbulent vortex. The bubbles in the water are torn up to produce more and smaller bubbles, so that larger gas-water contacting area is obtained so as to increase the ozone dissolving efficiency. When the turbulent vortex is more intense, the force to tear the bubble in the water is stronger, so that the bubbles in the water are smaller and the ozone dissolves more efficiently. 
         [0020]    The mixing pump shown in  FIG. 2 ,  FIG. 3 , and  FIG. 4  is a vortex mixing pump. As shown in  FIG. 3 , the leaves  3  are provided on an outer circle portion of the impeller  2 , and the water inlet is provided on an outer circle of the mixing pump. The leaves  3  are provided on an outer circle portion of the impeller  2 , and form a radiating shape. The rotation of the impeller  2  drives the leaves  3  to move around so as to propel the water to speed up, so that kinetic and potential energy (pressure) of water is constantly increasing. A vortex mixing pump produces more intense turbulence vortex than a centrifugal mixing pump. Although it has lower converting efficiency from the mechanical energy of the impeller to the kinetic energy and pressure potential energy of the water; because the vortex mixing pump has more intense turbulence vortex than the centrifugal mixing pump, and the vortex mixing pump has a higher gas-water dissolving efficiency than that of the centrifugal mixing pump. Therefore, the vortex mixing pump is a better choice to be used in the gas-water mixing pump. 
         [0021]    The ozone gas can be added into the water before infusing into the mixing pump (premixing), or the ozone conduit  8  can be inserted into the mixing pump directly. Usually the inserting position is at the water inlet, as shown in  FIG. 3 . The permanent magnets A and B are positioned as near as possible to the outer edge to increase a diameter thereof, so that the moment arm of the permanent magnets A and B are increased, so when the torsion remains, the magnetic driving force can be reduced, which is shown in  FIGS. 1 ,  2 ,  3  and  4 . As shown in  FIGS. 1 and 2 , a rotor in the motor  6  is connected to the device for fastening the permanent magnet B  5  via a shaft to drive the permanent magnet B  5 . The motor shown in  FIG. 4  is a brushless DC motor. The rotor of the motor  6  is an annular magnet, and the stator with a winded coil is disposed inside the annular rotor. The rotor is connected to central shaft via a rotary plate, and the permanent magnet B  5  is mounted on the rotary plate. Such a structure is simple and compact. The brushless DC motor has high efficiency and long lifespan, and is safe and reliable, so as to be a great choice for household appliance. 
         [0022]    In order to make the most of the attraction between the permanent magnets A and B, and produce effective moment to drive impeller to rotate, the N-S polar direction of the permanent magnets A and B is the direction of the axis of the motor and the impeller, as shown in  FIG. 4 . Comparing with other arrangements, the magnetic line of force between the permanent magnets A and B is the shortest, and the attraction between the permanent magnets A and B is the strongest. When the permanent magnet B drives the permanent magnet A to rotate, due to the loading effect of the impeller, the permanent magnets A and B are dislocated; due to the fact that like poles repel while unlike poles attract, the adjacent permanent magnets A on the impeller  2  are arranged to have opposite polarity, as shown in  FIG. 3 . The corresponding two permanent magnets A and B have opposite polarity, so as to attract each other; the permanent magnet B and the permanent magnet A that are adjacent to the corresponding permanent magnet A therewith have same polarity, so as to repel each other. Because of the dislocation between the corresponding two permanent magnets A and B, the permanent magnet B has acting force with two adjacent permanent magnets A, wherein one is attraction, and the other is repellence, so that the magnetic force is fully taken. 
         [0023]    There are a variety of permanent magnets. The Nd—Fe—B is the best in terms of cost and magnetic intensity. Therefore, in the present invention, Nd—Fe—B is the first choice. The rotation of the permanent magnets A and B produce alternating magnetic field, especially between the permanent magnets A and the permanent magnets B. If the pump casing is made of metal, the alternating magnetic field produces electric eddy current, which has two major disadvantages. Firstly, electromagnetic field lowers the magnetic driving force between the permanent magnets A and B. Secondly, the electric eddy current produces heat and increases the load of the motor. Therefore, the pump casing, especially between the permanent magnets A and B, should be made of non-conductive and non-metal material. Plastic is easily shaped, low cost, and is capable of resisting oxidization and corrosion, so that the plastic completely meets the demand of the household appliance. In the present invention, plastic pump casing is the first choice. 
         [0024]    Referring to  FIG. 5  and  FIG. 6 , a vortex type of mixing pump of the present invention is illustrated. The motor is a brushless DC motor including a stator  14 , a rotor  12 , a motor shaft  13 , and a rotary plate  11 . The rotor  12  is firmly connected to the motor shaft  13  via rotary plate  11 . The permanent magnet B is partially imbedded in the rotary plate  11 . The pump casing  1  and the pump cover  15  are sealed by a sealing gasket  17 . The permanent magnet A ( 4 ) is entirely imbedded in the impeller  2 , so as to be separated from water, because the permanent magnet, usually made of iron-base material, easily gets rusty when contacting with water, especially ozone water. As shown in  FIG. 6 , the ozone gas enters into Venturi-tube  18  through ozone conduit  8 . The ozone gas is premixed into water through Venturi-tube  18 , before infusing into the mixing pump. Only through the intense turbulent vortex produced by the impeller of the mixing pump, can the big bubbles transform into many tiny bubbles, which helps the ozone dissolve into water. 
         [0025]    The vortex type of mixing pump shown in  FIG. 7  is similar to the mixing pump shown in  FIG. 5 . The major difference is that there are two water channels at both sides of the impeller  2 , as shown in  FIG. 5 , and there is only one water channel at left side of the impeller. The objective of such design is to dispose the permanent magnet A ( 4 ) more closely to the outer circle of the impeller  2 , so as to increase the magnetic driving torsion. 
         [0026]    One skilled in the art will understand that the embodiment of the present invention as shown in the drawings and described above is exemplary only and not intended to be limiting. 
         [0027]    It will thus be seen that the objects of the present invention have been fully and effectively achieved. It embodiments have been shown and described for the purposes of illustrating the functional and structural principles of the present invention and is subject to change without departure from such principles. Therefore, this invention includes all modifications encompassed within the spirit and scope of the following claims.

Technology Category: 2