US2719001A - Positive displacement pump with dual coacting flexible vane-type impellers - Google Patents

Description

Sept. 27, 1955 C. KNUTH POSITIVE DISPLACEMENT PUMP WITH DUALCOACTING FLEXIBLE VANE-TYPE IMPELLERS Fi led De 2 Sheets-She t 1 INVENTOR.

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POSITIVE DISPLACEMENT PUMP WITH DUALCOACTING FLEXIBLE VANE-TYPE IMPELLERS F5166. D60. 20, 1952 2 Sheets-Sheet 2 I IN V EN TOR.

United States Patent POSITIVE DISPLACEMENT PUMP WITH DUAL COACTING FLEXIBLE VANE-TYPE IlVIPELLERS Carl Knuth, Fond .du Lac, Wis., assiguor to Kiekhaefer Corporation, Cedarburg, Wis., a company of Wisconsin Application December 20, 1952, Serial No..327,079

3 Claims. (Cl. 230141) This invention relates to flexible vane-type, positive displacement blowers or pumps.

Theinvention provides a pump or blower which includes two impellers oppositely rotated in synchronization and having corresponding flexible vanes which approach and successively engage and depress each other in a generally medial plane respecting the rotational axes of the impellers.

An object of the invention is to provide more eflicient pump operation of flexible vane-type impellers.

Another object is to allow operation of flexible vanetype impellers at higher speeds to adapt the pump to various types of service such as air-blowers and superchargers for engines.

Another object is to reduce the frictional wear of the vanes of the impellers.

Another object is to increase the capacity of the blower or pump.

Another object is to increase the normal useful life of flexible vane-type pump impellers particularly for operation at high speeds.

These and other objects and advantages will be more fully set forth in the following description of the invention as illustrated in the accompanying drawings.

In the drawings:

Figure 1 is a transverse section showing the pump impellers in elevation as disposed within the pump housing; and

Fig. 2 is a longitudinal section through the pump housing on the axis of the impeller shafts showing the intermeshing gears which maintain the shafts and impellers in synchronization.

The pump 1, shown in the drawings, includes the parallel shafts 2 and 3 which carry the duplicate impellers 4 and 5, respectively. The housing 6 comprises the separable members 7 and 8 which are joined to form the impeller chamber 9 and enclose impellers 4 and therein. The bearings 10 journally support shafts 2 and 3 and are carried by members 7 and 8 on opposite sides of the respective impellers. The corresponding ends of shafts 2 and 3 carry the meshing gears 11 and 12 respectively and outside of housing 6.

The driving coupling member 14 is secured to shaft 3 adjacent to gear 12 and provides for operation of the pump by suitable drive means, not shown.

In the operation of pump 1, shafts 2 and 3 are driven in opposite directions to rotate impellers 4 and 5 at corresponding speeds and in opposite directions.

Each impeller includes a hub 15 and the tapered radially extending vanes 16 which are equally spaced about hub 15 and are of equal length. Each vane 16 is of flexible material and suitable construction which allows the vane to be deflected radially toward the axis of rotation. The impellers 4 and 5, shown in the drawings, illustrate a preferred construction wherein the hub 15 and vanes 16 are integrally formed of molded synthetic rubber and each hub 15 is bonded over the metal bushing 17 which is mounted directly on the respective shaft and rotationally secured thereto by the key 18. With the opposite rotation of the shafts, the respective vanes 16 are disposed in corresponding relation to approach and pass together between the shafts.

According to the invention, the diameter of each of impellers 4 and 5 is substantially greater than the distance between the axes of shafts 2 and 3 whereby the vanes approaching each other with rotation of the shafts provided for as described, are adapted to engage and deflect each other to effect a delivery of fluid by displacement of the volume of fluid therebetween.

The inner dimensions of chamber 9 comprise cylindrical sections which correspond generally to the combined dimensions of impellers 4 and 5 and which sections intersect to define a plane medial to the axes of shafts 2 and 3. The inlet and outlet connections 19 and 20 respectively, to and from chamber 9 are disposed generally in the plane referred to and on opposite sides of chamber 9. The dimensions of chamber 9 provide only the necessary operating clearances for impellers 4 and 5 to allow the impellers to be rotated with limited friction and leakage between the same and the walls of chamber 9.

The fluid entering chamber 9 through inlet 19 is carried around the outside of the chamber between the adjacent vanes 16 of each impeller to the outlet 20 where the approaching corresponding vanes engage at their outer extremities. With further rotation, the same vanes are deflected by their further face-to-face engagement to pass between shafts 2 and 3 and to effect the partial displacement of the fluid therebetween in the direction of outlet 20. During such engagement the following, or succeeding corresponding vanes more adjacent to outlet 20 engage sufliciently in advance of the release of the adjacent forward vanes to prevent intermediate loss of pressure of the fluid.

The displaced fluid is forced in the direction of outlet 20 under pressure. The vanes 16 of each impeller are radially spaced so that the subsequent engagement of corresponding vanes of each impeller occurs while such pressure is maintained to reduce pulsation. The fluid continues to be displaced by the engaging vanes to cushion the engagement of the next succeeding vanes and to prevent their eventual breakdown from their tipto-tip engagement at high speeds.

The undisplaced fluid is released in the direction of inlet 19 with the mutual disengagement of the vanes for recirculation with further rotation of shafts 2 and 3. Inlet 19 is located with respect to the released vanes 16 so that the velocity of the fluid entering chamber tends to retard the vanes and reduces the tendency of the vanes to whip as the same are successively released at high speeds. At such high speeds the fluid carried between vanes 16 and discharged in the direction of outlet 20 limits the impact of the vanes following as described whereby higher operating speeds are permitted Without breakdown of the vanes by the impacts thereof.

The invention utilizes flexible vane-type impellers which do not require machining to close tolerances for the necessary seal particularly in handling air or gases and adapts such vane-type impellers to higher operating speeds and corresponding greater deliveries.

The pump is intended for handling large quantities of gases at relatively low pressures and particularly as an engine supercharger.

Various embodiments of the invention may be employed within the scope of the accompanying claims.

I claim:

1. A positive displacement pump comprising two parallel shafts, intermeshing gears carried by and fixed on said shaft to synchronize their rotation in opposite directions, one of said shafts being adapted to be driven and to drive the other thereof through said gears, a housing including walls each extending normal to the axes of said shafts and having journal bearing means supporting said shafts, said housing having an outer body forming a chamber between said walls, a flexible vanetype impeller having a diameter greater than the distance between the axes of said shafts and mounted on each of said shafts and within said chamber, the outer dimensions of said chamber corresponding to the combined outer dimensions of said impellers and providing limited operating clearance therefor whereby adjacent vanes of each impeller are adapted to entrain a fixed volume of fluid therebetween, said impellers being fixed relative to said shafts to rotate therewith in opposite directions without inter-meshing and having corresponding vanes disposed to engage at their tips upon approaching each other with opposite rotation, said housing having an outlet opening from said chamber adjacent to said approaching vanes, said vanes upon engagement at their tips and with further opposite rotation being flexible to bend on each other generally in a plane extending medially of said shafts to discharge the entrained fluid, said housing having an inlet opening for the admission of the fluid to the chamber at the point of mutual release of the corresponding vanes after movement thereof from between said shafts.

2. The invention as defined in claim 1 wherein the discharge of fluid by the engagement of corresponding vanes is effected in the direction of the outlet and between the following corresponding vanes approaching each other to reduce the impact of their engagement.

3. The invention as defined in claim 1 wherein the inlet is located so that the fluid entering the chamber is effective to be directed against the vanes passing between the shafts and to cushion the release of said vanes.

References Cited in the file of this patent UNITED STATES PATENTS 26,962 Adams Jan. 31, 1860 263,196 Morse Aug. 22, 1882 2,403,796 Hanna July 9, 1946 2,407,753 Wallgren Sept. 17, 1946 2,451,603 Barker Oct. 19, 1948 2,467,524 Fernstrum Apr. 19, 1949 2,567,699 Devlin Sept. 11, 1951 2,572,334 Guibert Oct. 23, 1951

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