US2968253A

US2968253A - Rotary pump

Info

Publication number: US2968253A
Application number: US765086A
Authority: US
Inventors: Autio Paul
Original assignee: Individual
Current assignee: Individual
Priority date: 1958-10-03
Filing date: 1958-10-03
Publication date: 1961-01-17
Anticipated expiration: 1978-01-17

Description

Jan. 17, 1961 P. ALJ-no ROTARY PUMP Filed oct. :5, V1958 l/ Paul Hu fio INV EN TOR.

Unite This invention relates to rotary pumps, and more particularly to pumps suitable for pumping a fluid mass containing abrasive or other solid material entrained therein. Such fluids are exemplified by abrasive containing sludges, and certain solid-liquid mixtures wherein the liquid of the mixtures is employed as a transferring medium for the solids of the mixtures. Illustrative of the latter type of mixtures is the ground and splintered bone, meat, and water mixtures which are pumped as feed for certain carnivorous animals. The pump of the invention is characterized by a number of novel features which contribute to a long and trouble-free life for the pump, and running of the pump without its jamming or locking up.

Generally, it is an object of the invention to provide, in a rotary pump having a housing and impeller blades rotatable in the housing, mechanism for moving the blades in their mounting radially in and out in such a way that a stream or jet of the uid pumped by the pump is ejected past the outer end of each blade as the blade moves next to the usual outlet port of the pump, whereby the blade extremity is cleaned of any sol d matter which otherwise might tend to lodge on the blade end and cause jamming and wear in the pump.

Another object is to provide a construction for moving such impeller blades radially to and fro which is positive in action and can take long and sustained use without appreciable wear.

In the art to which this pump relates, it is a known expedient to mount the impeller blades of a pump eccentrically in a substantially cylindrical pump chamber, so that the blades are moved about a rotation axis which States Patent-O is offset radially from the center axis of the pump chamber. The blades are loosely mounted, and move to and fro during operation. As a result of the eccentricity of their mounting relative to the cylindrical boundary wall of the pump chamber, adjacent pairs of blades and the boundary wall define a moving, liquid conlining chamber of diminishing cross-section progressing from the inlet to the outlet port of the pump. Thus compression of the uid handled takes place. This invention contemplates, in such a pump having eccentrically arranged impeller blades and a mounting for the blades accommodating shifting movement thereof relative to the impeller rotation axis, means positively actuating the blades producing a shifting movement wherein the ends of the blades are kept snugly against the cylindrical boundary wall during most of their movement from the inlet to the outlet port for the pump, and then moved away from the cylindrical pump chamber boundary wall slightly before coming into registry with the outlet port of the pump. The result is a construction wherein the liquid confining chamber defined by an adjacent blades and the cylindrical wall is opened to the outlet port prior to the time the leading blade which denes the chamber moves over the outlet port. As a consequence, a thin jet of uid is forced over the expanse of the leading blade, and a cleaning or washing action takes place which functions to remove any matter lodged on the blade end.

Fice

A common feed employed in a mink farm comprises a mixture of water and comminuted meat and bone material. This may be delivered to various feed stations using a pump. With conventional pumps, bone chipsV and other solid matter collecting on the moving pump parts has caused jamming of the pump and frequent failures. The pump of this invention, by reason of the cleaning action discussed, has been used in suchapplications with quite satisfactory results.

The invention also features the use of a novel cam mechanism moving the blades to and fro on their eccentric mounting. Specifically, a camintegral withV the pump housing is provided which rides against enlarged abutment shoulders carried by the impeller blade elements. The abutment shoulders have enlarged bearing surfaces which engage the cam,.and these surfaces'are constructed so as to withstand long hours of operation without noticeable wear.

These and other 'objects and advantages are attained by the invention, which is described hereinbelow in conjunction with the accompanying drawings wherein:

Fig. 1 is a plan view of a rotary pump constructed according to an embodiment of this invention, with portions ofthe pump housing removed and illustrating various parts of the pump, and, in dotted outlines, various working positions of blade elements in the pump; and

Fig. 2 is a section View along the line 2-2 in Fig. 1, showing further details of the pump construction.

Referring now to the drawings, 10 indicates generally a pump housing comprisinga substantially cylindrical boundary wall 12, and oppositely disposed

end wall portions

14 and 16.

Walls

12, 14 and 16 deline together a substantially cylindrical pumpV chamber within the interior of the pump housing. To enable assembly of the pump components, wall V16 is shown as an end plate detachable from cylindrical boundary wall 12.

Walls

12 and 14 are integral' with each other.

Wall or plate 16 has around the perimeter thereof an annular ange portion 18 which projects radially outwardly of wall 12.

Slots

20, 21 formed in diametrically opposite positions of flange portion 18 receive the shanks of a pair of

swivel screws

22, 23, which are pivotally mounted by pins 24 on sets of lugs 26 integral with cylindrical wall 12. Plate 16 is secured in place as in Fig. 2, by swinging

screws

22, 23 to a vertical position with the shanks of the screws in

slots

20, 21, and turning wing nuts 28 downwardly on the externally threaded ends of the swivel screws.

Rotatably mounted within the confines of the pump chamber is an impeller mechanism or means indicated generally at 30. The impeller mechanism is rotatable about a rotation axis indicated at 32 (see Fig. 2), which is radially offset from the center axis of the cylindrical pump chamber.

Impeller mechanism 30 comprises a substantially cylindrical core or mounting hub portion 36, a circular plate portion 38 integral with hub 36 and supporting the hub on wall 14, and a drive shaft portion 40 integral with plate 38 which extends downwardly and outwardly through the end wall 14. End wall 14 is provided with a sleeve portion 42 encircling shaft portion 40. The pump is actuated by a suitable motor (not shown) rotating shaft 40.

The outer surface or Wall of hub portion 36 lies at its closest to the inner surface of wall 12 along a line where the inner surface of Wall 12 is closest to the rotation axis 32 of the impeller. The end o-f such a line is indicated in Fig. 1 at A. Proceeding in a counterclockwise direction from this line in Fig. 1 (which, in operation -of the pump, is the direction of rotation of the impeller means) the outer surface of hub 36 diverges from the inner surface of wall 12 until a point of maximum separation between the two is reached, which is along a line Where the inner surface of wall 12 lies at its maxmium distance from axis 32. Th's l'ne is indica'ed at B in Fig. l and is along a dametrically opposite side of wall 12. Continuing from line B, the Walls of hub 36 and wall 12 converge until line A is reached.

An inlet port is provided which cmrnunz'cates with the pump chamber at an area where the hub wall and wall 12 are diverging. An outlet port is prov'ded wh'ch communicates with the pump chamber at an area where the hub wall and wall 12 are converging. The outlet port is angularly spaced about the rotation axis of the impeller means from the inlet port. Flufd, in moving from the inlet to the outlet port, is subjected to compression, as the fluid is transported between the two ports through a liquid confining chamber of diminishing crosssection.

More specifically, loosely mounted on hub 36 for movement to and fro radially of the impeller rotation axis are a pair of crossed

impeller blade elements

50, 51. These are arranged at right angles to each other, so that the ends of the blade elements are spaced at regular angular modules about axis 32. The blade elements have a length slightly less than the leng h of the shortest chord subtended by curved wall 12 which passes through axis 32. Blade element 50 occup'es the position of such a chord, and it may be seen, with reference to Fig. l, that the length of element 50 is such as to allow slight radial play of the element when in the position shown.

Blade elements S0, 51 are mounted for reciprocation in

slots

56, 57, 58 and 59 formed in the walls of hub 36. These slots extend from the top of hub 36 downwardly to the plane of the top of plate portion 38. Blade element 50 has outer end portions joined by a web portion 61 spaced closely to the base of the hub, whereas blade element 51 has outer end portions joined by a web portion 62 spaced upwardly from the base of hub 36 and overlying web portion 61.

The blade elements have

cutouts

66, 67 indented into their top edges. Cutout 67 of blade element 50 receives web portion 62 of blade element 51. The cutouts perform a further function. Thus,

upstanding edges

71, 72, 73 and 74 dening the side limits of the cutouts are expanded, and have a T-shaped cross section. These edges constitute abutment shoulders in the device. The radially inwardly facing outer surfaces of these edges are convexly curved, and provide enlarged bearing surfaces of substantially greater width than the thickness of a blade element.

Integral with detachable end wall 16, and projecting downwardly therefrom, is a kidney shaped noncircular cam 76. The cam fits within the hollow interior of hub 36 with the peripheral cam surface thereof contacting the abutment shoulders of the blade elements. Since the cam is in fixed position, and the impeller means is rotatable in the housing, movement of the irrpeller means causes the blade element to be shifted back and forth by cam 76.

The positioning of the cam relative to axis 32 is critical. Referring to Fig. l, it will be noted that the cam is positioned so that on movement of the imp-ller, the end of a blade element first is shifted outwardly against the inner surface of wall 12, progressing from a point C in Fig. 1 in a counterclockwise direction. The blade element end positively is forced against the inner surface of wall 12 until the blade element end reaches a point D. At this point the blade element end is shifted radially inwardly, over about a ten degree arc, with the opposite end of the blade element moving against the inner surface of wall 12. Thus the cam 76 has a cam surface engaging the abutment shoulders to position blade elements that includes a curved portion 76a that curves in a sweep coinciding with the locus described by the abutment shoulders with the blade portions snugly against said boundary wall and immedately prior to and during their initial movement from the inlet to the outlet ports. This causes the blade elements to pass snugly adjacent boundary wall 12 during their initial movement. The cam surface of cam 76 then has a receding portion 76b that recedes inwardly from such a locus during final movement of the blade portions between the inlet and outlet ports and when the blade elements approach the outlet port. This accommodates radially inward movement of the blade elements during this final movement.

Extending axially into the pump chamber and communicating with the chamber at a location spaced next to the path of movement of the sides of the blades elements is an inlet port 91. Port 91 has an elongated, substantially arcuate shape, conforming generally to the shape of the space between the wall of hub 36 and wall 12. Extending radially of the pump chamber and communicating with the chamber at a location spaced next to the path of movement of the ends of the blade elements is an outlet port 92. It will be noted that the inlet port lextends over to and ends at the area of maximum separation between the wall of hub 36 and wall 12. It will also be noted that the outlet port communicaes with the pump chamber at an area where the wall of hub 36 and wall 12 are converging.

The outlet port is angularly spaced about the rotation axis of the impeller means from the end of the inlet port an angular distance slightly in excess of degrees (about degrees). Thus two successive blade element ends, when in the position of ends 50a and 51a illustrated in Fig. 1, define with the wall of the hub 36 and wall 12 a liquid conning chamber which is closed off at both of its ends.

In operation, fluid flows into the pump chamber through the inlet port and collects in the space bounded on each end by a blade element end. On rotation of the impeller mechanism, liquid caught between successive blade ends is moved in the pump chamber until the blade ends occupy about the position of ends 50a, 51a. At this point, liquid carried between the ends of the blade elements tends to be compressed (due to the convergence of the wall of hub 36 and wall 12).

On continued movement of the impeller, the blade element end occupying the position of end 5`a starts to move radially inwardly. This opens up a small space between the end of the blade element and wall 12, and this opening of the space occurs before the end moves over port 92. As a result, a jet of liquid is forced over the end of the blade element, which clears away foreign matter such as chips 7S from the end of the blade element. Continued movement of the impeller places the leading blade element in full registry with the outlet port, and fiuid is discharged through the port.

With a blade element end in the position of blade end Slb in Fig. l, any solid caught between the outer surface of hub 36 and the inner surface of wall 12 can escape into the slot formed in hub 36 which slidably mounts the blade portion. On further rotation of the impeller, this material is ejected from the slot by move- Vment of the blade end radially outwardly from the hub.

By using an axia'ly extending inlet port, the ends of the blade elements are prevented from catching up large amounts of solid matter at the infeed end of the pump. On the other hand, a radially extending outlet port is provided, in order that discharge of fluid take place over vthe ends of the blade elements.

While a blade end moves away from Wall 12 before reaching the outlet port, it does not do so until the following blade end has closed off the inlet port. Thus the inlet and outlet ports are never open directly to each other, and the pump is a positive displacement pump.

I claim:

1. ln a rotary pump, a housing having a substantially cylindrical boundary wall and oppositely disposed end walls dening the side and radially outer limits of a cy lindrical pump chamber, a mounting hub rotatably mounted within said pump chamber for rotation about a rotation axis parallel to and offset radially from the center axis of said pump chamber, said hub having a cylindrical hub wall concentric with said rotation axis and defining the radially inner limits of said pump chamber, said hub Wall along one side thereof being positioned snugly adjacent one side of said cylindrical boundary wall, means defining inlet and outlet ports communicating with said pump chamber at locations disposed on each side of where the hub and boundary walls are snugly adjacent, said ports being connected within the housing by a converging portion of the pump chamber that is defined by converging hub and boundary walls, said hub during operation of the pump rotating in a direction wherein the wall of the hub moves from said inlet to said outlet port in said converging portion of the pump chamber, plural crossed impeller blade elements mounted on said hub with opposite end portions extending radially outwardly from said rotation axis and rotatable with said hub, said hub being provided with slot means accommodating radial shifting of the blade elements on the hub, the end portions of said blade elements being regularly angularly spaced on the hub and the spacing between successive end portions being less than the angular spacing of the inlet and outlet ports in said converging portion of the pump chamber, and means positively for shifting the blade elements radially to and fro, said means comprising opposed and radially inwardly facing abutment shoulders integral with each blade element7 and `a stationary noncircular cam element occupying a plane extending transversely of said rotation axis and projecting between the abutment shoulders of each blade element, said cam element having a curved surface constructed to bear against an abutment shoulder of a blade element so as to force an end portion thereof snugly adjacent said boundary Wall throughout all but final movement of the end portion from said inlet to said outlet port and during final movement to bear against an abutment shoulder so as to shift the end portion away from said boundary wall, said final movement starting at substantially the time the next following end portion starts beyond said inlet port, such movement of the blade elements in the converging portion of the pump chamber resulting in a flow of uid over the end portions of the blade elements during their such iinal movement.

2. The pump of claim 1 wherein said outlet port com- Y municates with said pump chamber through said cylindrical boundary wall.

References Cited in the tile of this patent UNITED STATES PATENTS 19,581 Peirce Mar. 9, 1858 115,254 Tenant May 23, 1871 333,356 Taber Dec. 29, 1885 629,796 Lobee Aug. 1, 1899 1,407,620 Ambrose Feb. 21, 1922 1,922,951 Hawley Aug. 15, 1933 FOREIGN PATENTS 70,672 Switzerland of 1915 74,754 Austria Oct. 10, 1918 597,560 France Sept. 5, 1925 671,192 France Aug. 31, 1929