Impeller for a liquid pump

A centrifugal pump impeller is providing that has vanes of a configuration that enhances pumping efficiency. The impeller has a base with a connector boss located at a center of rotation and a plurality of vanes extending from the base in spaced relation about the boss. Each vane having a leading end edge adjacent the boss and a trailing end edge adjacent an outer periphery of the base. Each of the trailing end edges being disposed parallel to an axis of rotation of the base, and each of the leading end edges being inclined forwardly at an angle relative to an operative rotational direction of the impeller and being spaced from the boss. For each vane, the leading end edge thereof is disposed at an acute angle relative to the trailing end edge thereof.

BACKGROUND

The present invention relates to an impeller design for liquid pumps, and more particularly, to an impeller for centrifugal water pumps for circulating cooling water through internal combustion engines, such as internal combustion engines for use in motor vehicles. The impeller can also be utilized in pumps for other purposes and for liquids other than water.

Water pumps designed to provide cooling water to internal combustion engines conventionally have a casing containing a pumping chamber, a driven impeller to pump water by centrifugal force, an inlet aligned axially with the impeller and an outlet whose initial channel is tangent to the impeller vanes. The vanes of the impellers have uniformly been of a constant thickness, arcuate in shape and tangent to a circle drawn about the axis of the impeller. The vanes slope backwardly from their inner end to their outer end and force the water to the outlet.

U.S. Pat. No. 6,398,498 B1 discloses an impeller for water pumps. The present invention provides an impeller for liquid pumps that is an improvement on the impeller disclosed in U.S. Pat. No. 6,398,498 B1.

U.S. Pat. No. 6,398,498 B1 discloses feathered vanes arranged on a base rotatable in a housing. For instance, see FIG. 3 of U.S. Pat. No. 6,398,498 B1. The housing disclosed therein has an axial inlet and a radial outlet. The impeller rotates to pump fluid from the inlet to the radial outlet. This is customary for centrifugal liquid pumps that had either prior art constant thickness vanes as disclosed in FIG. 1 of U.S. Pat. No. 6,398,498 B1 or the improved feathered vanes disclosed in FIG. 2 of U.S. Pat. No. 6,398,498 B1.

With the foregoing in mind, an object of the present invention is to provide a novel impeller for water pumps which is effective in pumping water or other liquids. A further object of the present invention is to provide a novel impeller for a centrifugal pump, such as a water pump for a motor vehicle which, for the same or less power requirement as a conventional similar size pump will pump a greater quantity of water, permitting the engine to run cooler and therefore generate more useful power. A still further object of the present invention is to provide an impeller that functions even better than the impellers disclosed in U.S. Pat. No. 6,398,498 B1.

DETAILED DESCRIPTION

FIG. 1illustrates a liquid pump having the same overall configuration as that disclosed in U.S. Pat. No. 6,398,498 B1, but incorporating the impeller of the present invention. The pump includes a pump housing28which has a water inlet passage30leading to the center of an impeller14and an outlet passage32extending from the periphery of the impeller14. The impeller14is positioned and contained within a pumping chamber33located between the inlet and outlet passages,30and32. The impeller14has a mounting boss18which is mounted on a shaft26for rotating the impeller14about a rotational axis A in a direction as shown by arrow “B” inFIG. 1.

As best shown inFIGS. 2 and 3, the impeller14has a series of vanes22(a total of six vanes22as illustrated) provided on a disc-shaped base16. The vanes22and base16are configured to fit in the pumping chamber33with slight clearances relative to juxtaposed pumping chamber surfaces as customary in centrifugal pumps. Thus, when the shaft26is rotated, the vanes22cooperate with fluid in the pumping chamber33to force the flow of fluid from the inlet passage30to the outlet passage32.

In the impeller disclosed in U.S. Pat. No. 6,398,498 B1, the major extent of the vane's cambered length is disposed relatively more tangent the rotational axis of the base than radially thereof. The improvements made in the present invention reside in providing vanes with a novel configuration and location on the impeller that significantly enhances pumping efficiency.

As illustrated inFIG. 2, the impeller16has six (6) vanes22. Each vane22is identical to the other. Each vane22has a leading end portion22aand a trailing end portion22bdisposed in circumferentially separate locations on the flat disc base18. The leading end portion22aof each vane22is located in closely spaced relation with the centrally located mounting boss18that connects the impeller14to the mounting shaft26. With respect to the operative rotational direction of the impeller14, the leading end portion22ais radially closer to the rotational axis of the impeller than the trailing end portion22b.

Each vane22has a leading end edge22cand a trailing end edge22d. The leading end edge22cinclines forwardly at an angle relative to the impeller base16and is disposed closely adjacent the cylindrical outer surface of the mounting boss18. The trailing end edge22dis disposed adjacent the outer periphery of the impeller base16, and it is disposed parallel with the rotational axis A of the impeller base16. The leading end edge22cdeclines slightly backward from where it connects to the impeller base16adjacent the mounting boss18.

Each vane22is formed with a camber (i.e., is curved) and has a medial part of the camber extending between its leading edge22cand its trailing edge22d. On opposite sides of the camber are surfaces denominated in relation to the pumping rotational direction of the impeller, e.g. proceeding and receding. The leading, or proceeding surface22eis concave for about one-half the distance from the leading edge22cto the trailing edge22d, and then becomes convex at22ffrom that location to the trailing edge22d. The trailing, or receding, surface22gis continually convex in its entirety from the leading edge22cto the trailing edge22d. The thickness of each vane22is at its maximum at about one-half the length of the median between the vane surfaces.

The leading edge22cof each vane22is inclined at about a thirty (30°) angle from the base16. For instance, seeFIG. 4. The trailing edge22dis disposed orthogonal (90°) relative to the flat base16, i.e., extends parallel to the rotational axis A of the impeller14. The included angular disposition of the leading and trailing edges,22cand22d, is about thirty degrees (30°).

A prototype impeller, having a configuration as shown herein inFIGS. 2-4, was made from cast aluminum and tested in a stock housing used in a popular brand vehicle engine. The test was similar to the test disclosed in U.S. Pat. No. 6,398,498 B1.

FIG. 5is a graph showing the quantity of flow of cooling water through three water pumps for an internal combustion engine, each water pump being identical in size, at varying speeds. The pumps were driven by an electric motor controlled by a rheostat.

As shown inFIG. 5, two (2) slightly different versions of an impeller built in accordance with the present invention (i.e., having the configuration as shown herein ofFIGS. 2-4) showed significant differences in pumping capabilities over a full range of rotational speeds up to 6000 rpm relative to a stock impeller. (The lower line inFIG. 5corresponds to the stock impeller and the two upper lines correspond to the present invention.) At the maximum speed tested, the improved impeller pumped twice as much cooling fluid as the stock pump impeller.

While a particular embodiment of the present invention has been illustrated and described herein, it is not intended to limit the invention to such a disclosure and changes and modifications may be incorporated and embodied there within the scope of the accompanying claims.