US3340812A

US3340812A - Centrifugal pump

Info

Publication number: US3340812A
Application number: US468024A
Authority: US
Inventors: Schlesiger Klaus
Original assignee: SCHLESIGER AND CO KG
Current assignee: SCHLESIGER AND CO KG
Priority date: 1964-07-01
Filing date: 1965-06-29
Publication date: 1967-09-12
Anticipated expiration: 1984-09-12
Also published as: DE1453759B2; CH432246A; SE316081B; DE1453759A1; GB1096876A; NL146911B; AT255912B; NL6508344A; BE666122A

Description

1967- KUSCHLESlGER 3,340,812 CENTRIFUGAL PUMP Filed June 29. 1965 INVENTOP KLA us SCHLES/GEZ ATT 7- United States Patent 11 Claims. 61. 103-103 This invention relates to a novel centrifugal pump and, in particular, to a centrifugal pump having a rotor operating within the interior of a spiral housing into which liquid is introduced through a suction socket.

The efficiency of conventional pumps is adversely affected and materially reduced by the presence of longfibrous or other type solid matter in the liquid which is being pumped. Devices, such as grids, have been used when pumping such solid-carrying liquids for the purpose of separating the solid matter from the liquid during the pumping operation, but these have generally not proved satisfactory. It has also been proposed that such pumps should act as grinders for reducing the size of the solid matter. In such pumps a wall of the pump housing opposite a vane or paddle wheel is provided with grooves or recesses which are intended to grind the soild matter in a gap between the paddle wheel and the pump housing as the paddle wheel rotates. However, in such pumps it is still possible for solid or foreign matter to become clogged in the gap between the vanes and the pump housing, particularly when the foreign matter is stones,

pieces of metal or similar solids which are not readily broken up by the grinding operation. Furthermore, due to the fact that the entire liquid intake is ground by such pumps an uneconomical loss in efliciency inevitably results, together with heavy wear, intense noise and undesirable vibration. In addition there is an increased danger of scum formation due to the fine pulverization of solid fibrous material. This is highly undesirable in purification plant applications because the scum prevents the access of oxygen to the liquid.

To avoid clogging of conventional pumps it has also been common to employ a rotor which is provided with but only one vane or blade. In such pumps the solid matter can pass through the pumps in an unobstructed or unhindered manner, but the pumps have the disadvantages of imposing heavier stresses on bearings, reducing the pump efficiency, uneven running, and a lower output than pumps of the multi-vane type.

In accordance with the above, it is a primary object of the present invention to obviate the above-mentioned disadvantages in conventional pumps and to provide a novel centrifugal pump in which solid matter can be reduced in size without adversely affecting the efliciency of the pump.

Acccording to the present invention a centrifugal pump is provided which has a rotor operating within a spiraltype housing, into the interior of which projects a suction intake socket, and a collar forming an extension of the suction socket which extends into the interior of the pump chamber and terminates in an inclined edge serving as a cutter whereby solid material is reduced in size without the above-noted disadvantages of unconventional pumps. Other objects and advantages of the invention will be apparent from the following description with reference being made to the accompanying drawing in which: FIG. 1 is an axial sectional view through a centrifugal pump constructed according to the present invention, and illustrates a multi-vane rotor in the interior of a pump chamber rotatable about an extension of a suction intake; and

- FIG. 2 is a cross-sectional view taken generally on line II-II of FIG. 1, and illustrates the generally spiral configuration of the pump chamber.

Referring to the drawing, a centrifugal pump con structed in accordance with this invention comprises a spiral-shaped housing 1 in which is rotatably mounted a paddle wheel 2 having two vanes 3 and 4. The paddle Wheel 2 is journaled in a roller bearing 5 and is driven through a shaft 6 by convention-a1 drive means 7, such as an electric motor. A suction intake socket or inlet 8 opens into the interior of the housing 1 in 'a direction toward the paddle wheel 2. A spiral channel or volume 9 leads from the inlet 8 to an outlet 10. The inlet 8 is extended axially upwardly to form a tubular collar 11 having an inclined upper'cutting edge 12. The collar 11 only partially encircles the inlet 8, as is best illustrated in FIG. 2 of the drawing. A sector 13 of the collar 11 is cut-away and opens towards a portion of the channel 9 which lies immediately adjacent the outlet 10. The upper edge 12 of the collar '11 extends up to the lower face of a plate 2a of the paddle wheel 2 on which the vanes 3, 4 are mounted. From the plate 2a the edge 12 falls away vertically at a vertical edge 14. In the sector 13 a portion 15 of the collar 11 is of reduced height and terminates in a horizontal edge 15a such that a gap 16 exists be tween the lower end faces of the vanes 3, 4 and a base 18 of the housing 1. The portion 15 prevents material, cs pecially fibrous material, from finding its way through the gap 16.

Liquid is drawn upwardly through the inlet 8 into the pump housing 1 and is rotated by the rotation of the paddle wheel 2 and the vanes 3, 4. The liquid is directed along the spiral channel 9 and is discharged from the housing 1 through the outlet 10. As the paddle wheel 2 rotates, larger or bulkier solid matter is shredded by the vanes 3, 4 operating in conjunction with the inclined cutting edge 12 of the collar 11 as the liquid is drawn over the cutting edge 12. Any shreds of the solid matter which may cling to the outer edges of the guide vanes 3, 4 are removed at a cutting edge 17 adjacent the outlet 10 of the housing 1.

If desired, the collar 11 may be secured to the housing so as to be detachable and replaceable, as by being threaded into the intake socket 8.

By the use of the collar 11 functioning as a cutter and forming an integral portion of the suction inlet 8, the paddle wheel 2 acts as a closed rotor since foreign matter direct from the suction inlet 8 can not lodge between the vanes 3, 4 and the wall 18 of the housing 1. The material passing over the cutting edge 12 into the flow channel 9 has no noticeable directional component relative to the open gap 16 and solid matter located in the center of the paddle wheel 2 tends to move outwardly without reverse flow downwardly toward the inlet 8. Because of this, long objects inclined in a diametrical direction are pushed upwardly over the cutting edge 12 and are shredded thereby. Since only one cutting edge 12 is present, the power provided for shredding is at such a level that motors of relatively low output may be employed while still insuring that practically all the solid matter is cut. There is no possibility of the pump being overloaded by excessive frictional forces during grinding, nor can the pump be clogged by the solid matter after it passes the collar 11 because of the raised extension 15 and the progressively increased cross-section of the chan nel 9 from the inlet 8 to the outlet 10.

A particular advantage of the pump resides in its economy of operation because not all solid matter is reduced. Rather, only those objects are cut which either might cause damage and are in the process of flowing ofi the vanes 3, 4, or objects which are still within the range of the cutting edge just as it rises. In this connection, it

has been found that an object which is about to pass into the pump channel 9 and is seized by the collar 11, is ejected rather than cut by the collar because, in the lower plane of the cutting edge 12 the speed of flow at the collar 12 increased but the cutting operation has not yet begun. The cutting operation does not occur at the upper part of the collar until the space between the cutting edge 12 and the surface of the plate 2a has become smaller than the cross-section of the object. It has also been observed that objects which approach the collar 11 shortly before it presents its greatest height to the plate 2a, still do not flow into contact with the cutting edge 12 due to the sudden deceleration of flow, but are propelled directly through the unrestricted sector or portion 13 by the collar 11. Since only a tiny fraction of solid matter is actually engaged by the collar cutting edge 12, the cutting edge 12 has a long working life, sometimes actually equal to that of the pump itself. Furthermore, the cutting edge 12 avoids cutting stones and the like which pass through the pump without difficulty; the cutting edge 12 becoming effective only in cases where the solid matter shows an obstructive tendency as it flows through the pump.

The pump of this invention thus retains its high operational efliciency, runs extremely quietly, and is very reliable in operation. Only those objects are shredded by the cutting edge 12 which would cause rotor stoppage, while all other bulky objects pass through the pump uncut.

What is claimed as new is:

1. A centrifugal pump comprising a housing, said housing including an inlet and an outlet, a rotor journaled for rotation in said housing, at least one vane carried by said rotor, said inlet including a generally tubular hollow cylindrical extension projecting into said housing toward said rotor, said at least one vane being rotatable about said extension, said extension terminating at an innermost circumferentially inclined cutting edge, and a portion of said extension adjacent said outlet being relieved to provide substantially unrestricted flow of a liquid from said inlet to said outlet.

2. The centrifugal pump as defined in claim 1 wherein said housing includes a cutting edge adjacent said outlet and cooperative with said vanes for removing material from the vanes as the latter rotates past said last-mentioned cutting edge.

3. A centrifugal pump comprising a housing, said housing including an inlet and an outlet, a rotor journaled for rotation in said housing, at least one vane carried by said rotor, said inlet including an extension projecting into said housing toward said rotor, said at least one vane being rotatable about said extension, said extension terminating at an innermost inclined cutting edge, a portion ,of said extension adjacent said outlet being relieved to provide substantially unrestricted flow of a liquid from said inlet to said outlet, said housing has a lower wall in spaced relationship to lowermost edges of said vanes to define a gap therewith, and the relieved portion of said extension being defined in part by a wall portion of a height slightly less than the height of said gap.

4. A centrifugal pump comprising a housing, said housing including an inlet and an outlet, a rotor journaled for rotation in said housing, at least one vane carried by said rotor, said inlet including an extension projecting into said housing toward said rotor, said at least one vane being rotatable about said extension, said extension terminating at an innermost inclined cutting edge, a portion of said extension adjacent said outlet being relieved to provide substantially unrestricted flow of a liquid from said inlet to said outlet, said relieved portion is defined by a'vertical edge adjacent the higher side of said inclined cutting edge and a generally horizontal edge between a lowermost portion of said vertical edge and the low side of said inclined cutting edge.

5. A centrifugal pump comprising a generally cylindrical housing, said housing including an inlet and an outlet,

a rotor journaled for rotation in said housing, the axis of rotation of said rotor being offset from the axis of said cylindrical housing thereby defining a generally spiral channel diverging toward said outlet, a plurality of vanes carried by said rot-or, said inlet including an extension projecting into said housing, said vanes being rotatable about said extension, said extension being generally tubular in configuration and having a circumferentially inclined cutting edge, and a portion of said extension adjacent said outlet being relieved to provide substantially unrestricted flow of a liquid from said inlet to said outlet.

6. A centrifugal pump comprising a generally cylindrical housing, said housing including an inlet and an outlet, a rotor journaled for rotation in said housing, the axis of rotation of said rotor being offset from the axis of said cylindrical housing thereby defining a generally spiral channel diverging toward said outlet, a plurality of vanes carried by said rotor, said inlet including an extension projecting into said housing, said vanes being rotatable about said extension, said extension being generally tubular in configuration and having an inclined cutting edge, and a portion of said extension adjacent said outlet being relieved to provide substantially unrestricted flow of a liquid from said inlet to said outlet, said housing having a lower wall in spaced relationship to lowermost edges of said vanes to define a gap therewith, and the relieved portion of said extension being partially defined by a wall portion of a height slightly less than the height of said gap.

7. A centrifugal pump comprising a generally cylindrical housing, said housing including an inlet and an outlet, a rotor journaled for rotation in said housing, the axis of rotation of said rotor being offset from the axis of said cylindrical housing thereby defining a generally spiral channel diverging toward said outlet, a plurality of vanes carried by said rotor, said inlet including an extension projecting into said housing, said vanes being rotatable about said extension, said extension being generally tubular in configuration and having an inclined cutting edge, a portion of said extension adjacent said outlet being relieved to provide substantially unrestricted flow of a liquid from said inlet to said outlet, and said housing includes a cutting edge adjacent said outlet and cooperative with said vanes for removing material from the vanes as the latter rotate past said last mentioned cutting edge.

8. A centrifugal pump comprising a generally cylindrical housing, said housing including an inlet and an outlet, a rotor journaled for rotation in said housing, the axis of rotation of said rotor being offset from the axis of said cylindrical housing thereby defining a generally spiral channel diverging toward said outlet, a plurality of vanes carried by said rotor, said inlet including an extension projecting into said housing, said vanes being rotatable about said extension, said extension being generally tubular in configuration and having an inclined cutting edge, a portion of said extension adjacent said outlet being relieved to provide substantially unrestricted flow of a liquid from said inlet to said outlet, said housing having a lower wall in spaced relationship to lowermost edges of said vanes to define a gap therewith, the relieved portion of said extension being defined by a wall portion of a height slightly less than the height of said gap, and said wall portion extending between a lowermost portion of said inclined cutting edge and a vertical edge depending from an uppermost portion of said inclined cutting edge.

9. A pump comprising a housing, said housing including spaced walls defining a chamber therebetween, an inlet in one of said walls opening toward the other of said walls, vane means in said housing adapted for rotation therein for delivering a medium from the inlet toward the outlet, cutting means in said chamber, said cutting means including a cutting edge inclined circumferentially from said one wall toward said other wall, said cutting edge being a portion of a generally hollow cylindrical collar, said cutting edge having circumferentially opposite end portions, and means defining a generally radially opening relieved area between said opposite end portions.

10. The pump as defined in claim 9 wherein said relieved area is defined by an edge generally parallel to the axis of said inlet which is adjacent a higher side of said cutting edge and a generally horizontal edge between a lowermost portion of said vertical edge and a lower side of said cutting edge.

11. The pump as defined in claim 9 wherein said one wall is in spaced relationship with said vane means to define a gap therewith, and said relieved area is defined in part by a wall portion of a height less than the height of said gap.

References Cited UNITED STATES PATENTS 1,094,836 4/1914 De Laval 103-111 12/1918 Duda 103-111 10/1925 Dupont 103111.1 6/1940 Riebel 103-111 7/ 1943 Dibovsky 1031 11 6/1959 Umbicht 103111.1 7/1963 Anderson 103111.1 7/1966 Daniel 103103 FOREIGN PATENTS 10/ 1949 France.

4/ 1959 Great Britain. 1/ 1913 Switzerland.

DONLEY .T. STOCKING, Primary Examiner. 15 HENRY F. RADUAZO, Examiner.

Claims

1. A CENTRIFUGAL PUMP COMPRISING A HOUSING, SAID HOUSING INCLUDING AN INLET AND AN OUTLET, A ROTOR JOURNALED FOR ROTATION IN SAID HOUSING, AT LEAST ONE VANE CARRIED BY SAID ROTOR, SAID INLET INCLUDING A GENERALLY TUBULAR HOLLOW CYLINDRICAL EXTENSION PROJECTING INTO SAID HOUSING TOWARD SAID ROTOR, SAID AT LEAST ONE VANE BEING ROTATABLE ABOUT