EP1640617A2 - Free vortex pump - Google Patents

Abstract

An electric water pump rotating in the correct direction, comprising a water pump body (2) that has a chamber (3), which is basically cylindrical in shape, and a chamber cover (8), which is fitted at the axial outward end of said chamber (3); an impeller (42) is accommodated and rotates inside said chamber (3) coaxially; said impeller (42) includes at least two impeller vanes (45) that project from the impeller disc surface (44) and said impeller vanes (45) bend to the same direction around the rotating axis OO' of said disc surface (44); Assuming V as the volume inside said chamber (3) and v as the volume enveloped by all the said impeller vanes (45) when said impeller (42) rotates, a design can be made about relations of geometrical parameters between volume of said chamber (3) in said electric water pump and said volume enveloped by all the impeller vane (45) rotating inside said chamber (3) to be in the following range, i.e., ratio between volume enveloped by all the said impeller vane (45) in rotation and volume of said chamber (3): $$\text{v/V = 0.08 ∼ 0.18}$$

Description

• Technical Field This invention is directed to the structure of non-positive-displacement rotary pump, especially involving fitting dimensions of impeller and chamber of the radial pump for liquids and particularly involving chamber dimensions of the single-phase electric centrifugal water pump.
• Background Art The non-positive-displacement rotary pumps include the radial and axial pumps for liquids. Most of the existing radial pumps for liquids are centrifugal water pumps as shown in Fig.1. Impeller 42 rotates inside the water chamber 3 and said impeller 42 is usually installed in the same shaft of the permanent magnet rotor 41 of the electric motor to form the impeller assembly 4. Structure of said impeller 42 is in the structure of many vertical impeller vanes 45 on a rotating disc 44 as shown in Fig.2. Considering liquid dynamic characteristics and improvement of water output efficiency, it is a common practice to design the intersection lines of said impeller vanes 45 and said rotating disc 44 to be arcs facing to the same rotating direction, in another word, said impeller vanes 45 have arc surfaces bending to the same direction around the rotating axis OO' of said disc 44. Obviously, only when said impeller 42 rotates against the bending direction of said impeller vanes in said chamber 3, can water output be at a higher efficiency and the resistance against the driving machine caused by the liquid be less.
  Rotary water pumps can be driven by machines or hydraulic power, however, most centrifugal pumps are driven by electricity and existing electric motors driving centrifugal water pumps are basically single-phase AC synchronous or asynchronous motors for common applications of small power. The permanent magnet rotor single-phase synchronous motors are simple in structure, light in weight and low in cost, especially appropriate for driving centrifugal water pumps in common applications. However, the single-phase synchronous or asynchronous motors usually don't have, or have little, starting torque, and the rotating direction is not definite when the motors are just started. Any disturbance will cause the rotors rotate in either direction and continue to rotate faster and faster in the same direction, in another word, rotating direction of the single-phase synchronous or asynchronous motors is indefinite while said centrifugal water pumps need a definite rotating direction, i.e., to the direction against that of all the impeller vanes 45 bend to, as shown by the arrow R in Fig.2. Only in this way, can the water pumps have higher output efficiency. Prior art solves the problem in the following way: inserting two sets of windings into stators of said electric motors to make said driving motors run as two-phase electric motors by utilization of split-phase capacitors, thus making the motors have definite rotating direction. This approach not only increases costs of said electric motors, but also needs a capacitor added, which is not an ideal solution.
• Disclosure of the Invention This invention aims to overcome demerits of the prior art by an electrically driven water pump that can rotate in the correct direction automatically, i.e., the direction against that of all the impeller vanes bending to, in order to provide the markets with a kind of electrically driven high-efficient water pump that is simple in structure, low in cost and easy in using single-phase electrical power supply, which can ensure correct rotating direction.
  Technical approach of the current invention to said problem can be realized by the following embodiment: design and manufacture a kind of electric water pump that can rotate in the correct direction automatically, comprising a water pump body that has a chamber, which is basically cylindrical in shape, and a chamber cover, which is fitted at the axial outward end of said chamber; an impeller is accommodated and rotates inside said chamber coaxially; said impeller includes at least two impeller vanes that project from the impeller disc surface and said impeller vanes bend to the same direction around the rotating axis OO' of said disc surface. Assuming V as the volume inside said chamber and v as the volume enveloped by all the said impeller vane when said impeller rotates, a design can be made about relations of geometrical parameters between volume of said chamber in said electric water pump and said volume enveloped by all the impeller vane rotating inside said chamber to be in the following range, i.e., ratio between volume enveloped by all the said impeller vane in rotation and volume of said chamber: $$\mathrm{v}/\mathrm{V}=0.08\sim \mathrm{0.18.}$$

  

  
  then said impeller will rotate in the direction against that of all the impeller vanes bend to, and liquid resistance will be less and water output higher at this time.
  Technical problems that the current invention aims to approach can be solved by a similar technical embodiment: design and manufacture a kind of electric water pump, comprising a water pump body, that has a chamber, which is basically cylindrical in shape, and a chamber cover, which is fitted at the axial outward end of said chamber; an impeller is accommodated and rotates inside said chamber coaxially; said impeller includes at least two impeller vanes that project from the impeller disc surface and said impeller vanes bend to the same direction around the rotating axis OO' of said disc surface. Assuming D and H as the internal diameter and axial height of said chamber, d and h as the diameter of volume enveloped by all the the impeller vane and axial height of all the impeller vane when said impeller rotates, a design can be made about relations of geometrical parameters between volume inside said chamber and said volume enveloped by all the impeller vane rotating inside said chamber to be in the following range, i.e., ratio between diameter of the volume enveloped by all the said impeller vanes in rotation and diameter of volume of said chamber: $$\mathrm{d}/\mathrm{D}=0.618\sim 0.820,$$

  

  and ratio between axial height of the vanes and axial height of the chamber, $$\mathrm{h}/\mathrm{H}=0.12\sim \mathrm{0.38.}$$

  

  
  then said impeller will rotate in the direction against that of all the impeller vane bend to, and liquid resistance will be less and water output higher at this time.
  Compared with the prior art, the electric water pump in the current invention has a correct design in relations of geometrical parameters between its chamber volume and the impeller rotating inside said chamber, making said impeller have to rotate in the correct direction, i.e., against the bending direction of said impeller vanes, to realize the minimum liquid resistance and higher output efficiency, thus making it possible to install the single-phase synchronous or asynchronous motors, which are simple in structure and low in cost, to drive said water pumps while ensuring correct rotating direction each time when said water pumps are started with high output.
• Brief Description of the Drawings Fig.1 is an exploded view of structure of the current invention, an electric water pump that can rotate in the correct direction required. The arrow A in the figure indicates the direction in which the driving electric motor is inserted into the pump body;
• Fig.2 is a three-dimensional sketch of the impeller 42 in the current invention of electric water pump;
• Fig.3 is a three-dimensional sketch of the water pump body 2;
• Fig.4 is an orthographic front view of said water pump body 2;
• Fig.5 is a cross-section M-M of the water pump body 2 in Fig.4;
• Fig.6 is an orthographic front view of the impeller 42 inside said water pump;
• Fig.7 is a right view of the impeller 42 in Fig.6.
Best Mode and Other Embodiments of the Invention Further introduction is made in combination with the attached drawings. The current invention of an electric water pump that can rotate in the correct direction required as shown in Fig.1 to Fig.7, comprising a water pump body 2, in which there is a chamber 3 basically cylindrical in shape and a chamber cover 8 is installed at the axial outward end of said chamber 3; said impeller 42 is accommodated and rotates co-axially in chamber 3; said impeller 42 has at least two vanes 45 projecting vertically on the rotating disc 44 of the impeller, and all the vanes 45 bend to the same direction around the rotating axis OO' of said disc 44. Assuming V as the inner volume of said chamber 3 and v as the volume enveloped by all the said impeller vane 45 when said impeller 42 rotates. Under the condition of said chamber being basically cylindrical or truncated cone with small taper in shape, there will be
• $$\mathrm{V}=\frac{\mathrm{\pi }}{4}{\mathrm{D}}^2\mathrm{H}\mathrm{\hspace{1em}}\mathrm{v}=\frac{\mathrm{\pi }}{4}{\mathrm{d}}^2\mathrm{h};$$

  

  
  design the geometrical parameters of volume of said electric water pump chamber 3 and said impeller 42 rotating inside said chamber to meet the following relation, i.e., ratio between the volume enveloped by all the impeller vanes when said impeller rotates and the volume of the chamber shall be $$\mathrm{v}/\mathrm{V}=0.08\sim 0.18,$$

  

  
  then said impeller 42 will rotate in the direction against that of all the impeller vanes bend to, and the liquid resistance will be smaller and water output higher.
• The same electric water pump that can rotate in the correct direction required as shown in Fig.1 to Fig.7, comprising a water pump body 2, in which there is a chamber 3 basically cylindrical in shape and a chamber cover 8 is installed at the axial outward end of said chamber 3; said impeller 42 is accommodated and rotates co-axially in chamber 3; said impeller 42 has at least two vanes 45 standing vertically on the rotating disc 44 of the impeller, and all the vanes 45 bend to the same direction around the rotating axis OO' of said disc 44. Assuming D and H as the inner diameter of said chamber 3 and its axial height, respectively; assuming d and h as the diameter of the volume enveloped by all the said impeller vane 45 when said impeller 42 rotates and axial height of said impeller vanes, respectively. Design the geometrical parameters of volume of said electric water pump chamber 3 and said impeller 42 rotating inside said chamber to meet the following relation, i.e., diameter of the volume enveloped by all the said impeller vane to diameter of the said chamber when said impeller rotates shall be $$\mathrm{d}/\mathrm{D}=0.618\sim 0.820,$$

  

  and the axial height of impeller vanes to the height of chamber
  shall be $$\mathrm{h}/\mathrm{H}=0.12\sim 0.38,$$

  

  
  then said impeller 42 will rotate in the direction against that the impeller vanes 45 bend to, and the liquid resistance will be smaller and water output higher.
• Preferred embodiment of the current invention can also be the same electric water pump that can rotate in the correct direction required as shown in Fig.1 to Fig.7, and design the geometrical parameters of volume of said electric water pump chamber 3 and said impeller 42 rotating inside said chamber to meet the following relations at the same time.
• ① Diameter of the volume enveloped by all the said impeller vanes to diameter of said chamber when said impeller rotates shall be d / D = 0.618 ~ 0.820, and the axial height of impeller vanes to the height of chamber shall be h / H = 0.12 ~ 0.38; and also
• ② The volume enveloped by all the said impeller vane to volume of the said chamber when said impeller rotates shall be v/V = 0.08 ~ 0.18. In these conditions, said impeller 42 will rotate in the direction against that the impeller vanes 45 bend to, and the liquid resistance will be smaller and water output higher.
  In the current invention, quantity of the vanes 45 on the electric water pump impeller 42 is 2 to 8 as shown in Fig.2 and 6. Among the preferred embodiments of the electric water pumps designed by matching the geometrical parameters of the chamber 3 and said impeller 42, the most representative ones have the following parameters:
  • 1. The diameter D of said chamber 3 is 45mm, the axial height H 16mm; the diameter d of said impeller 42 rotating inside said chamber is 29mm and the axial height h of said impeller vanes 6mm. The quantity of said impeller vanes is 5.
  • 2. The diameter D of said chamber 3 is 48mm, the axial height H 20.7mm; the diameter d of said impeller 42 rotating inside said chamber is 32.5mm and the axial height h of said impeller vanes 8mm. The quantity of said impeller vanes is 5.
  • 3. The diameter D of said chamber 3 is 56mm, the axial height H 23mm; the diameter d of said impeller 42 rotating inside said chamber is 38mm and the axial height h of said impeller vanes 8.5mm. The quantity of said impeller vanes is 5.
  • 4. The diameter D of said chamber 3 is 60mm, the axial height H 26mm; the diameter d of said impeller 42 rotating inside said chamber is 42mm and the axial height h of said impeller vanes 10mm. The quantity of said impeller vanes is 5, too.
    The said quantity of the vanes 45 on the electric water pump impeller 42 is permitted to be in the range of 2 to 15.
    It has been proved by practice that electric water pumps in the above-mentioned preferred embodiments of the current invention can automatically rotate in the correct direction required and go into normal operation status right after connected to a single-phase power supply network.

Claims (9)

1. An electric water pump rotating in the correct direction, comprising
   a water pump body (2) that has a chamber (3), which is basically cylindrical in shape, and a chamber cover (8), which is fitted at the axial outward end of said chamber (3);
   an impeller (42) is accommodated and rotates inside said chamber (3) coaxially;
   said impeller (42) includes at least two impeller vanes (45) that project from the impeller disc surface (44) and said impeller vanes (45) bend to the same direction around the rotating axis OO' of said disc surface (44);
   being characterized in that,
   Assuming V as the volume inside said chamber (3) and v as the volume enveloped by all the said impeller vanes (45) when said impeller (42) rotates, a design can be made about relations of geometrical parameters between volume of said chamber (3) in said electric water pump and said volume enveloped by all the impeller vanes (45) rotating inside said chamber (3) to be in the following range, i.e., ratio between volume enveloped by all the said impeller vanes (45) in rotation and volume of said chamber (3): $$\mathrm{v}/\mathrm{V}=0.08\sim 0.18,$$

   

   
   then said impeller (42) will rotate in the direction against that of all the impeller vanes (45) bend to, and liquid resistance will be less and water output higher at this time.
2. An electric water pump according to claim 1, being characterized in that,
   Assuming D and H as the internal diameter and axial height of said chamber (3), d and h as the diameter of volume enveloped by all the the impeller vanes (45) and axial height of all the impeller vanes (45) when said impeller (42) rotates, a design can be made also about relations of geometrical parameters between volume of said chamber (3) in said electric water pump and said volume enveloped by all the impeller vanes (45) rotating inside said chamber (3) to be in the following range, i.e., ratio between diameter of the volume enveloped by all the said impeller vanes (45) in rotation and diameter of volume of said chamber (3): $$\mathrm{d}/\mathrm{D}=0.618\sim 0.820,$$

   

   
   and ratio between axial height of the vanes (45) and axial height of the chamber (3), $$\mathrm{h}/\mathrm{H}=0.12\sim \mathrm{0.38.}$$

   

   
   then said impeller (42) will rotate in the direction against that of all the impeller vanes (45) bend to, and liquid resistance will be less and water output higher at this time.
3. An electric water pump rotating in the correct direction, comprising
   a water pump body (2) that has a chamber (3), which is basically cylindrical in shape, and a chamber cover (8), which is fitted at the axial outward end of said chamber (3);
   an impeller (42) is accommodated and rotates inside said chamber (3) coaxially;
   said impeller (42) includes at least two impeller vanes (45) that project from the impeller disc surface (44) and said impeller vanes (45) bend to the same direction around the rotating axis OO' of said disc surface (44);
   being characterized in that,
   Assuming D and H as the internal diameter and axial height of said chamber (3), d and h as the diameter of volume enveloped by all the the impeller vanes (45) and axial height of all the impeller vanes (45) when said impeller (42) rotates, a design can be made also about relations of geometrical parameters between volume of said chamber (3) in said electric water pump and said volume enveloped by all the impeller vanes (45) rotating inside said chamber (3) to be in the following range, i.e., ratio between diameter of the volume enveloped by all the said impeller vanes (45) in rotation and diameter of volume of said chamber (3): $$\mathrm{d}/\mathrm{D}=0.618\sim 0.820,$$

   

   
   and ratio between axial height of the vanes (45) and axial height of the chamber (3), $$\mathrm{h}/\mathrm{H}=0.12\sim \mathrm{0.38.}$$

   

   
   then said impeller (42) will rotate in the direction against that of all the impeller vanes (45) bend to, and liquid resistance will be less and water output higher at this time.
4. An electric water pump according to any one of claims 1 to 3, being characterized in that quantity of the vanes (45) on the electric water pump impeller (42) is 2 to 8.
5. An electric water pump according to any one of claims 1 to 3, being characterized in that the diameter D of said chamber (3) is 45mm, the axial height H 16mm; the diameter d of said impeller (42) rotating inside said chamber (3) is 29mm and the axial height h of said impeller vanes (45) 6mm; the quantity of said impeller vanes (45) is 5.
6. An electric water pump according to any one of claims 1 to 3, being characterized in that the diameter D of said chamber (3) is 48mm, the axial height H 20.7mm; the diameter d of said impeller (42) rotating inside said chamber (3) is 32.5mm and the axial height h of said impeller vanes (45) 8mm; the quantity of said impeller vanes (45) is 5.
7. An electric water pump according to any one of claims 1 to 3, being characterized in that the diameter D of said chamber (3) is 56mm, the axial height H 23mm; the diameter d of said impeller (42) rotating inside said chamber (3) is 38mm and the axial height h of said impeller vanes (45) 8.5mm; the quantity of said impeller vanes (45) is 5.
8. An electric water pump according to any one of claims 1 to 3, being characterized in that the diameter D of said chamber (3) is 60mm, the axial height H 26mm; the diameter d of said impeller (42) rotating inside said chamber (3) is 42mm and the axial height h of said impeller vanes (45) 10mm; the quantity of said impeller vanes (45) is 5.
9. An electric water pump according to any one of claims 1 to 3, being characterized in that quantity of the vanes (45) on the electric water pump impeller (42) is 2 to 15 .

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