Rotary kinetic fluid motors or pumps – Working fluid passage or distributing means associated with... – Casing having tangential inlet or outlet
Patent
1997-03-18
2000-04-04
Kwon, John
Rotary kinetic fluid motors or pumps
Working fluid passage or distributing means associated with...
Casing having tangential inlet or outlet
4152081, F04D 2944
Patent
active
060453265
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to new axial flow pumps improving the qualities of the currently available conventional pumps.
2. Discussion of Background Information
Centrifugal pumps include a motor driven impeller and a spiral stationary stator to provide a pressurized fluid output. FIGS. 1a and 1b show a diagram of a conventional centrifugal pump, including an Impeller R, a Spiral V, an Outlet S, and Inlet E, and an Impeller eye O.
In the conventional centrifugal pump, at least two major difficulties are encountered as follows: i.e., the return of the water to the impeller eye, with a decrease in suction; and the very fast whirl of the liquid "breaks the threads", creates cavitation, and wears out the buckets of the impeller, with a resultant loss in efficiency.
SUMMARY OF THE INVENTION
The device according to the invention is constituted by a tube attached on the impeller, and extends from the impeller eye up to the pump flange. By this structure, sealing is easier to obtain and maintain (o-rings for example).
The tube is provided with an internal spiral forming an Archimedes' tube with a hollow center (or equivalent vanes). The internal spiral is a known surface: helical with a constant-angle director cone. Thus, there is a mechanical pre-whirl of the liquid in the tube which rotates at high speed, before it reaches the impeller eye. This translates into a "saturation" of the impeller, a reduction in the cavitation and the resultant wear of the impeller.
Further, if the tube is extended, it can serve as an electric motor shaft, with the rotor attached on the tube, forming a unitary motor pump. If the pump is characterized by the extension of the tube to serve as the electric motor shaft, the shaft is attached on the motor rotor.
From this arrangement, it can be seen that the liquid directly cools the rotor, and therefore the electric motor. The cooling fan, blades, etc. can be suppressed.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1a is a side sectional view of a conventional centrifugal pump;
FIG. 1b is an inlet end view of the pump of FIG. 1a;
FIG. 2a is a side sectional view of the spiral tube of the present invention;
FIG. 2b is a side sectional view of the pump of the present invention including the spiral tube of FIG. 2a;
FIG. 2c is an enlarged sectional view of components of FIG. 2b; and,
FIG. 3 is a side sectional view of a unitary motor pump.
DETAILED DESCRIPTION OF THE INVENTION
As shown in FIGS. 2a-2c and 3, the device according to the invention is constituted by a tube Tu attached on the impeller R, and extends from the impeller eye up to the pump flange. By this structure, sealing is easier to obtain and maintain (O-rings J for example).
The tube is provided with an internal spiral AR forming an Archimedes' tube with a hollow center "a" (or equivalent vanes). FIG. 2a shows detail of the Archimedes' spiral with hollow center, where "a" is a free diameter. FIG. 2b shows an impeller R mounted with the new tube (and seals J). FIG. 2c shows the same impeller R, tubes Tu, and internal spiral AR, (where "Pr" in FIG. 3 indicates water progression in a tube Tu of the same configuration) and showing seals J, the motor M, the Motor flange Fl, and the tube Tu. The internal spiral AR is a known surface: helical with a constant-angle director cone. It is well known that an Archimedes' or Archimedean spiral is defined as a plane curve having an equation in polar coordinates (r, .theta.) of r.sup.m =a.sup.m .theta., where a and m are integers. Thus, there is a mechanical pre-whirl of the liquid PR in the tube Tu which rotates at high speed, before the liquid reaches the impeller R eye. This translates into a "saturation" of the impeller R or forced flow ("gavage" in French--"stuffing" or "cramming") to the impeller R. The impeller R thereby receives forced flow at increased pressure ("Gavage"), while whirling, and reducing cavitation and wear of the impeller R. The size of the impeller R, of the tube Tu and of the spiral AR are determined accordi
REFERENCES:
patent: 2524269 (1950-10-01), Patterson
patent: 3723028 (1973-03-01), Bottoms et al.
patent: 5451139 (1995-09-01), Tadiello
patent: 5597287 (1997-01-01), Helmick
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