US3478690A

US3478690A - Recirculating system for a self-contained sewage unit

Info

Publication number: US3478690A
Application number: US694322A
Authority: US
Inventors: Robert C Helke; Wayne E Sturgeon
Original assignee: Koehler Dayton Inc
Current assignee: Kidde Inc; Koehler Dayton Inc
Priority date: 1967-12-28
Filing date: 1967-12-28
Publication date: 1969-11-18
Anticipated expiration: 1986-11-18

Description

Nov. 18, 1969 R, c HELKE' ET AL 3,478,690

RECIRCULATING SYSTEM FOR A SELF-CONTAINED SEWAGE UNIT Filed Dec. 28, 1967 3 Sheets-Sheet Nov. 18, 1969 R. c. HELKE ET AL 3,478,690

RECIRCULATING SYSTEM FOR A SELF-CONTAINED SEWAGE UNIT Filed Dec. 28, 1967- :5 Sheets-Sheet rs United States Patent 3,478,690 RECIRCULATING SYSTEM FOR A SELF- CONTAINED SEWAGE UNIT Robert C. Helke, Dayton, and Wayne E. Sturgeon, Xenia, Ohio, assignors to Koehler-Dayton, Inc., Dayton, Ohio, a corporation of Ohio Filed Dec. 28, 1967, Ser. No. 694,322 Int. Cl. F04d 3/02; F04b 21/00; E03d 11/10 US. Cl. 10393 18 Claims ABSTRACT OF THE DISCLOSURE A recirculating system having an axial flow pump with an upper outlet and a lower inlet formed by a bell-shaped ditfusor; a slotted filter supported for rotation around the ditfusor and having a plurality of axially spaced peripheral slots each receiving a cleaning plate. A reversible motor connected to one shaft for rotating the filter in opposite directions and to another shaft supporting two axial flow impellers each having a single vane providing surfaces extending transversely in opposite directions relative to the shaft. One of the vanes positioned adjacent the diffusor and the other adjacent the outletand cooperating to produce a single direction, axial flow of liquid within the chamber regardless of the direction of rotation of the motor.

BACKGROUND OF THE INVENTION In a self-contained sewage unit as disclosed in US. Patent No. 3,067,433, assigned to the assignee of the present invention, a recirculating pump system is employed for flushing the bowl into a storage tank and in-. corporates an axial flow pump having a vertically extending cylindrical pumping chamber with a lower axially extending inlet and an upper radially extending outlet. An axial flow screw-type impeller is positioned within the pumping chamber and is supported by the lower end portion of a vertically extending shaft connected to a drive motor.

Surrounding the lower inlet of the pump is a cupshaped filter which is constructed by a series of rings spaced to define peripheral slots therebetween. The filter is driven by an auxiliary drive shaft connected to the drive motor which is adapted to be momentarily reversed at the beginning of each cycle so that the filter slots are eifectively cleaned by a series of stationary scraper or wiper plates projecting inwardly into the slots. It is also possible to hold the filter body stationary and rotate the wipers, as in US. Patent No. 3,342,341.

It has been found that an axial flow pump is ideally suited for a recirculating system for a self-contained sewage unit as it provides a high volume flow at a relatively low pressure and is especially quiet during operation. As disclosed in the above patent, one means for assuring effective cleaning of the filter slots is to reverse momentarily the direction of rotation of the filter at the beginning of each cycle of operation. It has also been proposed to alternate the direction of rotation of the motor and filter during successive cycles. In the latter case, however, the conventional screw-type axial flow impeller will not pump liquid from the inlet to the outlet when the ice SUMMARY 01 THE INVENTION The present invention is directed to an improved recirculating system for a self-contained sewage unit and as a primary feature incorporates a novel axial fiowimpeller which is effective to pump liquid always in one direction regardless of its direction of rotation. Thus the impeller of the invention is particularly suited for use in a sewage unit having a drive motor which reverses its direction of rotation in successive cycles for purposes of cleaning the filter, and in addition, provides the desirable features of quiet operation and a high volume low pressure flow of an axial fiow pump. A number of different forms of such an impeller are disclosed.

The recirculating system of the invention is also capable of use with a low head of liquid surrounding the filter without producing aeration of air binding of the pumping chamber, which commonly occurs with a low head of liquid as a result of cavitation. This latter feature is provided primarily by the use of ditfusor vanes located at the lower end of the pumping chamber adjacent the inlet of the axial fiow pump.

In accordance with a preferred embodiment of the invention, the recirculating system incorporates two axially spaced impellers mounted on the lower end portion of the impeller drive shaft, with each impeller including a single radially projecting vane having generally a triangular cross-sectional configuration. The axially spaced vanes are disposed from each other relative to the shaft with the lower vane disposed adjacent the diifusor vanes and the upper vane adjacent the outlet.

More specific features and advantages of the recirculating system constructed in accordance with the invention will be apparent from the following description, the accompanying drawings and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an axial section view of a recirculating system constructed in accordance with the invention;

FIG. 2 is a section view taken generally along the line 2-2 of FIG. 1;

FIG. 3 is a fragmentary view taken generally along the line 3-3 of FIG. 1;

FIG. 4 is a fragmentary section taken generally along the line 44 of FIG. 1;

FIG. 5 is an elevational view of a single vane impeller similar to the impeller shown in FIGS. 1-4 but having a modified vane configuration;

FIG. 6 is a perspective view of a twin fixed vane impeller constructed in accordance with the invention;

FIG. 7 is a perspective view of a twin tilt vane impeller constructed in accordance with the invention;

FIG. 8 is an elevational view of a twin flexible vane impeller constructed in accordance with the invention;

FIGS. 9 and 10 are elevational views of another twin fixed vane impeller showing a modification of the impeller of FIG. 6;

FIG. 11 is an elevational view of another single fixed vane impeller showing a modification of the impeller illustrated in FIGS. 1-4; and

FIG. 12 is a fragmentary axial section of the lower portion of the recirculating system showing a modification of the pump inlet and diifusor vanes.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings, the recirculating system shown in FIG. 1 is similar to the systems disclosed in the above identified US. patents. Specifically, the system of the invention incorporates a housing 1-0 which is preferably molded from a rigid plastic material, and includes an upper portion 12 defining a chamber 13. The upper portion 12 includes an outwardly projecting flange 14 attached to the underneath surface of a generally flat cover member 15 by a series of peripherally spaced screws 16 threaded into a backup mounting ring 17. The cover member 15 projects outwardly beyond the flange 14 and provides a peripheral flange 19 which seats on the cover 20 for a tank (not shown) so that the housing depends into the tank chamber in a manner similar to that shown in FIG. 2 of the above patent.

A centrally located cylindrical bore 24 is formed within the housing 10 and extends downwardly from the chamber 13 to a slightly smaller cylindrical pumping chamber 25 formed in part by a tubular lower end portion 26 of the housing 10. An annular diflusor 30 is mounted on the lower end of the housing portion 26 and includes a bell-shaped portion 31 having an inner surface 32 which curves uniformly from the inner cylindrical surface of the housing portion 26 to a generally radially plane thereby defining an inlet 33 for the chamber 25. The difiusor 30 also includes a series of four uniformly spaced stationary vanes 34 which project radially inwardly from the inner curved surface 32 of the bell-shaped portion 31.

An outlet passageway 38 is formed within the housing 10 and curves at its lower end to intersect radially the upper end portion of the pumping chamber 25. The upper end portion of the outlet passageway 38 is formed by a tubular portion 40 which projects upwardly through a hole 41 formed within the cover member and is sealed thereto by an O-ring 42. As disclosed in FIG. 3 of the above patent, the tubular portion 40 is connected to the flush bowl by a suitable flexible e'lbow.

A reversible electric motor 45 has a lower flange 46 which mounts upon the cover member 15 and is secured by a series of screws 47. The motor 45 includes a drive shaft 50 which extends downwardly through the chamber 13, bore 24 and pumping chamber 25. The shaft 50 is Supported by sleeve-type bearing 52 retained Within a housing 55 having an upper flange 56 secured to the housing 10 by a series of peripheral screws 57. A flange 58 forms the lower end portion of the bearing retaining housing 55 and has an external groove receiving an O-ring 61 and an internal counterbore 62 receiving an O-ring 64 surrounding the shaft 50. The O-ring 64 is retained within the counterbore 62 by an inverted cupshaped washer 66.

An impeller 70 is mounted on the shaft 50 within the upper portion of the chamber 25 and includes a tubular hub portion 71 rigidly secured to the shaft by a roll pin 72. The hub portion 71 has a lower curved nose surface 73 and an upper frusto-conical or tapered surface 74. A single vane 75 projects from the hub 71 and has a generally triangular or wedge-shaped cross-sectional configuration (FIG. 3). The vane 75 has two surfaces 76 (FIG. 3) which are positioned transversely relative to the axis of the shaft 50 in opposite directions and converge to form an upper radially extending edge 77. The lower end portion of each surface 76 curves outwardly joining a flat base surface 78 to form parallel spaced leading edges 79.

A second impeller 80 is mounted on the lower end portion of the shaft 50 and includes a hub portion 81 having a blind hole for the shaft and which is also secured to the shaft by a roll pin 72. The hub portion 81 has a lower inverted dome-shaped end surface 83 and a tapered upper surface 84 for streamlining the flow within the chamber 25. A single vane 85 projects radially from the hub portion 81 and is constructed identical to the vane 75. As shown, the lower impeller is positioned so that its vane sweeps close to the vanes 34 of the diifusor 30 defining the inlet 33, and upper impeller 70 is positioned so that its vane 75 sweeps the bottom portion of the outlet 38.

The housing 10 further includes an inverted cup-shaped lower portion surrounding the tubular portion 26 and which has a fiat bottom surface 91 and an internal cylindrical bearing surface 92 concentric with the cylindrical pumping chamber 25. A cup-shaped filter 95, also preferably formed of a rigid plastic material, includes an upper cylindrical portion 96 which seats for rotation on the surface 92 and includes inner-peripheral spur gear teeth 97. A peripheral flange 99 projects outwardly from the cylindrical portion 96 to provide a shoulder 100 which seats on the lower surface 91. The flange 99 is received within a corresponding counterbore 102 formed within a retaining ring 104 secured to the lower surface 91 of the portion 90 by a series of peripheral screws 106.

The filter 95 has a lower cylindrical portion having a series of axially spaced thin circumferential slots which divide the lower portion into a corresponding series of axially spaced rings 112. The rings 112 are integrally connected by a series of four axially extending ribs 114 which extend from the upper flange portion 99 to a flat circular bottom portion 115.

A vertically extending cavity is formed within the housing 10 and includes an upper counterbore 122 and a lower counterbore 123. An auxiliary drive shaft 125 extends through the cavity 120 and is supported at its upper end by a sleeve-type bearing 126 retained by an annular member 127 seated within the counterbore 122. A sleevetype bearing 128 is retained within the counterbore 123 and supports the lower end portion of the shaft 125. An O-ring 129 seals the lower end portion of the shaft 125 with the housing 10.

A spur gear is mounted on the lower end portion of the shaft 125 and engages the gear teeth 97 formed within the cylindrical portion 96 of the filter 95. Another spur gear 136 is rigidly mounted on the upper end portion of the shaft 125 and is driven through a gear train (not shown) by a pinion 138 mounted on the shaft 50 directly above an anti-friction thrust bearing 139 seated on the upper end of the bearing retaining housing 55.

A pin is secured within a hole 146 formed within the lower portion 90 of the housing 10 and extends downwardly parallel to the shaft 50. A series of generally triangular shaped scraper blades 150 have aligned holes for receiving the pin 145 and are arranged in vertical spaced relation to project inwardly into the corresponding slots 110. Each blade 150 is free to slide or float on the pin 145 to prevent binding with the adjacent rings 112. The blades 150 are prevented from rotating on the pin 145 by a retaining member having a cavity 156 conforming to receive the blades 150. The upper end portion of the retaining member 155 has arcuate slot 157 which receives a correspondingly shaped rib 158 projecting downwardly from the bearing ring 104 for positioning the retaining member 155 on the bearing ring and a screw 159 threaded into the lower end of the pin 145 secures the retaining member.

In operation of the recirculating system of the invention, the motor 45 reverses its direction of rotation for each cycle of operation from that of the previous cycle causing the drive shaft 125 to reverse alternately the direction of rotation of the filter 95. As a result of the construction and speed relation of the

vanes

75 and 85, the liquid which is filtered through the slots 110 is pumped from the inlet 33 to the outlet 38 in response to either direction of rotation of the shaft 50. Thus the

impellers

70 and 80 cooperate to form a single direction axial fiow pump regardless of the direction of rotation of the impellers.

Referring to FIGS. 5-11 which show various embodiments and modifications of a reversible single direction axial flow impeller constructed in accordance with the invention, an impeller 165 (FIG. 5) includes a tubular hub portion 166 having substantially the same configuration as the hub portion of the impeller 70 shown in FIG. 3. A single vane 170 projects radially from the hub portion 166 and has generally a wedge-shaped crosssectional configuration similar to the vane 75 shown in FIG. 3. The vane 170, however, has a flat trailing lip portion 171 of uniform thickness and which extends slightly transversely to the axis of the impeller to provide a flat surface adjoining a slightly curved surface 172 also extending generally transversely relative to the axis of the impeller. The opposite side of the lip portion 171 of the vane 170 forms a flat surface adjoining a slightly curved surface 173 which extends generally transversely to the rotatable axis of the impeller in a direction opposite to the surface 172. Thus in a manner similar to the surfaces 76 of the impeller shown in FIG. 3, the

surfaces

172 and 173 are effective to produce a single direction flow regardless of the direction of rotation of the impeller. The lip portion 171 aids in producing a somewhat higher discharge pressure. 7

An impeller 175 (FIG. 6) includes a cylindrical hub portion 176 from which two slightly curved vanes 178 project with the upper surfaces of the vanes extending transversely in opposite directions relative to the axis of the hub portion 176. The vanes 178 are positioned so that their lower leading edges 179 lie substantially within a plane extending through the rotatable axis of the impeller. Thus when the impeller 175 is rotated in opposite directions, the upper surfaces of the vanes 178 function in the same manner as the vane surfaces 76 of the impeller 70 or the vane surfaces 172 and 173 of the impeller 165, that is, to produce a single direction flow of water.

A plastic impeller 185 (FIG. 7) includes a cylindrical hub portion 186 having a pair of fiat integral ears 188 projecting radially to form a lower base portion. A pair of generally triangular shaped flat vanes 190 are formed integrally with the ears 188 of the hub portion 186 and are connected to the corresponding ears 188 by thin web hinge sections 191 so that the vanes 190 can pivot or tilt relative to the axis of the hub portion 186 in response to reverse rotation of the impeller 185. Preferably, the impeller 185 is constructed of polypropylene so that the hinge sections 191 will flex during long service without cracking or tearing.

A stop member or stud 192 projects from each side of each vane 190 and is adapted to engage the upper surface of the corresponding ear 188 to limit the tilting movement of each vane 190 relative to the hub portion 186. Thus when the direction of the impeller 185 is reversed, each vane 190 tilts alternately to one of the positions indicated by the dotted lines and thereby alternately provides liquid propelling surfaces which extend transversely in opposite directions relative to the rotational axis of the impeller.

A single direction axial flow impeller 195 (FIG. 8) has a cylindrical hub 196 which is secured to the shaft 50' by a cross pin 197. A collar or sleeve 198 seats on the upper end of the hub portion 196 and is free to rotate between stops (not shown) relative to the shaft 50'. A pair of diametrically arranged pins 200 are rigidly secured to the lower end portion of the impeller hub 196 and a corresponding pair of diametrically arranged pins 202 are secured to the collar 198 in parallel spaced relation to the pins 200. A flexible vane 205, constructed of rubber or other flexible material, extends between each corresponding pair of

pins

200 and 202. Thus when the direction of the shaft 50 is reversed, the collar 198 rotates on the shaft 50' between the stops so that opposite sides of each vane 205 alternately provide liquid propelling surfaces which extend in opposite transverse directions relative to the axis of the shaft 50' and thereby propel water in a single direction.

FIGS. 9 and 10 show an impeller 210 including a hub portion 211 having a configuration substantially the same as the hub portion of the lower impeller shown in FIG. 1. A pair of diametrically positioned fixed vanes 212 of substantially uniform thickness project radially from the hub portion 211, and both vanes 212 have an axially extending flat portion 214 which lie in a common plane offset radially relative to the rotary axis of the impeller. The flat portions 214 join corresponding flat coplanar base portions 215 which extend transversely in opposite directions relative to the rotational axis of the impeller. Thus the upper surfaces of the two fixed vanes 212 cooperate in a manner similar to the cooperation of the upper surfaces of the vanes 178 of the impeller 175 (FIG. 6) to provide liquid propelling surfaces which extend transversely in opposite directions relative to the rotational axis of the impeller and thereby provide a single direction axial flow impeller.

An impeller 220 (FIG. 11) includes a hub portion 221 having a configuration substantially the same as the hub portion 211 of the impeller 210 (FIG. 9) but includes a single vane 222 having a wedge-shaped crosssectional configuration similar to that of the vane 75 of the impeller 70 shown in FIG. 3. The impeller 22, however, is formed by converging slightly curved walls each having a uniform thickness. Thus it becomes apparent that the vane 222 of the impeller 220 is essentially produced by moving the vanes 178 of the impeller 175 (FIG. 6) closer together until the upper trailing edges of the vanes join. Therefore, from a functional standpoint, it is unnecessary for a single vane to have a solid generally wedge-shaped cross-sectional configuration as long as the vane provides at least two liquid propelling surfaces which are positioned generally transversely in opposite directions relative to the rotational axis of the impeller.

Referring to FIG. 12 showing a modification of a recirculating system constructed in accordance with the invention, the housing 10 has a lower end portion 26' which surrounds the lower impeller 80 and defines a circular inlet 33'. A filter includes a series of integrally formed radially extending dilfusor vanes 34' which project upwardly from the circular bottom portion and are spaced slightly below the lower end of the housing portion 26. Although the vanes 34 rotate with the filter 95', the vanes 34' function in the same manner as the vanes 34 (FIG. I), that is, to provide a smooth nonturbulent flow of liquid into the inlet 33'.

From the drawings and the above description, it can be seen that a self-contained sewage unit having a recirculating system constructed in accordance with the invention provides several desirable features and advantages. For example, the construction and arrangement of the

impellers

70 and 80, and especially the position of a single generally wedge-shaped vane 85 adjacent the inlet 33 defined by the diffusor 30 and the position of a single wedge-shaped vane 75 so that its leading edges 79 sweep the bottom of the outlet 38, assures a high volume flow to the outlet 38 along with a quiet opera tion of the pump for either direction of rotation of the shaft 50. The arrangement of the single vane on each impeller and the orientation of the vanes has also been found to provide an equally high pumping efiiciency for either direction of rotation of the impellers.

The arrangement of the diffusor vanes 34 and 34' also provides an important feature of the invention. That is, by employing a series of radially extending vanes 34 or 34' which project inwardly adjacent the lower impeller 80, the flow of liquid into the inlet 33 or 33' is smooth and quiet with minimum turbulence so that the pump can operate with a low head of water surrounding the filter 95 or 95' without producing cavitation. While the diffusor vanes are especially effective when used with the

impellers

70 and 80, it has been determined that the difiusor vanes may also be used with other impellers such as the screw-type impeller shown in the above patent for providing quiet operation and reducing cavitation of the pump when used with a low head of liquid within the tank.

The impeller modification shown in FIGS. -11 have been tested successfully and found effective for pumping liquid always in one direction from the inlet 33 to the outlet 38 in response to rotation of the impeller shaft 50 in either direction. The best combination of optimum performance and simplicity of manufacture, appears to be the arrangement of two axially spaced impellers each having a ingle generally wedge-shaped vane such as shown in FIGS. 3, 5 and 11, with the vanes disposed in 180 relationship.

What is claimed is:

1. In a self-contained sewage system including a pump housing with means defining a chamber having an inlet and an outlet, an annular filter surrounding said inlet and having a plurality of openings through which liquid flows to said inlet, means on said housing supporting said filter, a plurality of wiper members extending into said openings, means supporting said wiper members on said housing, a main drive shaft rotatably mounted within said housing, a reversible motor connected to said drive shaft, and auxiliary drive means connected to said shaft and connected to cause relative rotation between said filter and said wiper members in response to rotation of said drive shaft in opposite directions; the improvement comprising a reversible single direction axial flow impeller including a hub portion mounted on said shaft within said chamber, vane means projecting outwardly from said hub portion and providing at least two different liquid propelling surfaces, one of said surfaces extending transversely in one direction relative to the axis of said shaft and being effective to propel liquid axially of said housing from said inlet to said outlet in response to rotation of said shaft in one direction, and the other said surface extending transversely in an opposite direction relative to the axis of said shaft and being effective to propel the liquid axially of said housing in the same direction from said inlet to said outlet in response to rotation of said shaft in the opposite direction.

2. Apparatus as defined in claim 1 wherein said vane means include at least one vane having a generally wedge shaped cross-sectional configuration in a plane extending substantially parallel to the axis of said shaft, and said vane having opposite sides forming said surfaces.

3. Apparatus as defined in claim 1 wherein said pump housing defines a generally cylindrical chamber, said inlet disposed at one end of said chamber, said outlet extending generally radially from the opposite end of said chamber, said impeller including vane means positioned for rotation adjacent said inlet and separate vane means positioned for rotation adjacent said outlet, and each said vane means providing said two liquid propelling surfaces.

4. Apparatus as defined in claim 3 wherein each said vane means comprises a vane having a generally wedgeshaped cross-sectional configuration in a plane extending substantially parallel to said shaft.

5. Apparatus as defined in claim 4 wherein said vanes are positioned substantially 180 from each other in relation to said shaft.

6. Apparatus as defined in claim 3 wherein said impeller comprises an upper impeller having a single vane positioned for rotation adjacent said outlet, and a lower impeller having a single vane positioned for rotation adjacent said inlet.

7. Apparatus as defined in claim 6 wherein said lower impeller includes a hub portion having a generally pointed lower end surface for streamlining the flow of liquid into said inlet.

8. Apparatus as defined in claim 1 including a series of generally radially extending ditfusor vanes positioned adjacent said inlet for providing a smooth flow of liquid into said inlet.

9. Apparatus as defined in claim 8 including a bellshaped annular ditfusor member surrounding said inlet and having an inner surface curving smoothly from an axial direction to a radial direction to provide a smooth flow of liquid through said slots into said inlet, and said diifusor vanes projecting inwardly from said inner surface.

10. Apparatus as defined in claim 8 wherein said diffusor vanes are integral with said filter.

11. In apparatus for use on a self-contained sewage system and including a pump housing with means defining a chamber having an inlet and an outlet, an annular filter surrounding said inlet and having means defining a plurality of axially space-d peripheral slots through which liquid flows to said inlet, means on said housing supporting said filter for rotation on its axis, a corresponding plurality of wiper members extending into said slots, means connected to said housing and supporting said wiper members, a drive shaft rotatably mounted within said housing, a reversible motor connected to said drive shaft, auxiliary drive means connected to said shaft for rotating said filter in opposite directions in response to rotation of said drive shaft in opposite directions, and an impeller mounted on said shaft within said chamber; the improvement comprising a plurality of generally radially extending ditfusor vanes formed integrally with said filter and disposed adjacent said inlet to avoid cavitation during operation with a low head of liquid surrounding said dilfusor.

12. In an axial flow pump including a housing defining a pumping chamber having an inlet and an outlet and a shaft rotatable in said chamber, an improved reversible single direction axial flow impeller comprising a hub p rtion mounted on said shaft within said chamber, vane means projecting outwardly from said hub portion, said vane means providing at least two different liquid propelling surfaces, one of said surfaces extending transversely in one direction relative to the axis of said shaft and being effective to propel liquid axially of said housing from said inlet to said outlet in response to rotati n of said shaft in one direction, and the other said surface extending transversely in an opposite direction relative to the axis of said shaft and being effective to propel the liquid axially of said housing in the same direction from said inlet to said outlet in response to rotation of said shaft in the opposite direction.

13. An axial flow pump as defined in claim 12 wherein said vane means include at least one vane having a generally wedge-shaped cross-sectional configuration in a plane extending substantially parallel to the axis of said shaft, and said vane having opposite sides forming said surfaces.

14. A pump as defined in claim 12 wherein said vane means comprises a pair of diametrically opposed vanes mounted on said hub portion and each said vane providing one of said liquid propelling surfaces.

15. A pump as defined in claim 14 wherein each said vane has a substantially uniform wall thickness and includes a portion extending substantially parallel to the axis of said shaft and a portion extending transversely to the axis of said shaft, and said transversely extending portions of said vanes cooperatively providing said liquid propelling surfaces.

16. A pump as defined in claim 12 wherein said vane means includes at least one vane pivotally connected to said hu'b portion for movement between two transverse positions such that opposite sides of said vane alternately provide said liquid propelling surfaces in response to rotation of said impeller in opposite directions.

17. A pump as defined in claim 16 wherein said im- 3,067,433 12/1962 Dietz et al. 478 peller is formed of a plastic material and includes a thin 3,288,294 11/ 1966 Frey 10393 web section integrally connecting said vane to said hub 3,342,341 9/1967 Lee 478 portion'of said impeller. 3,356,221 12/1967 Katona et al. 478

18. A pump as defined in claim 12 wherein said vane 5 3,364,860 1/ 1968 Matzen 1033 means include at least one flexible vane, and means rotatably mounted on said shaft for supporting at least FOREIGN PATENTS a vane 678,531 1/1964 Canada.

593,633 5/ 1959 Italy.

References Cited 10 UNITED STATES PATENTS WILLIAM L. FREEH, Primary Examiner Couch 1033 Wade 103115 US. Cl. X.R. Fuqua 10393 15 478, 90; 103-220 Morgan 103-93