Feb. 10, 1942. I w. H. LANNERf 2,272,469

dENTRIFueAL PUMP Filed Dec. 25, 1939 INVENTOR.

ATTORNEY.

Patented Feb. 10, 194;

UNITED. "STATES amass tion of- Illinois Application December 23, 1939. Serial No. 310, 73

2 Claims. (Cl. 103-103) a from a suitable source of power such as an 'elec- This inventionrelates to centrifugal pumps of that type which are employed for pumping sewage and other' liquids containing solids such as paper, rags, stringy substances, trash and other semi-solids. Considerable difficulty has been encountered in centrifugal pumps of this typebecause of the likelihood of the rags, paperand other stringy material lodging on. or clinging to the heel of the impeller blade in such quantities as to interfere with the operation of the pump and sometimes clogging the same to such an ex-v tent that it must shut down. .Many attempts have been made to overcome this difllculty with more or less success, and the principal object of this invention is to eliminate the possibility of solids being caught blades.

I have accomplished this result by employing an entirely different principle of operation than has been employed heretofore in centrifugal pumps. In accordance with the present invention the interior of the Pu p is so shaped that the velocity of the liquid is increased as it passes through the eye of the impeller, then decreased in an inlet chamber,- and its velocity again increased as it passes the Heel of an impeller blade.

The result of this change of velocity of the 'liquid causes the solids to bunch together as the velocityis slowed up in the inlet chamber, and

the increase of velocityimmediately thereafter eausesthe solids to be drawn across the space in front of the heel of an impeller blade, thereby preventing the solids from being caught on the 7 heel. The invention consists, therefore, in the several novel features of construction, arrangement and combination of parts hereinafter fully .set forth and claimed.

The invention is clearly illustrated. in the drawing accompanying this specification, in which: I

Fig. 1 is a central vertical longitudinal section through to centrifugal pump, embodying a simple form of h broken away. I

Fig. 2 is a vertical cross section of theimpeller taken on the line 2-2 of Fig. 1.

r Fig. 3 is a vertical crosssectionof the impeller taken on the line 3-3 of Fig. l, and

Fig. 4'is a detailed horizontal cross section taken-on the line of Figs. 1 and}.

Referring to said drawing, the reference character I designates the, base of a" centrifugal pump, upon which is mounted a housing 8 containing bearings, one of'which is seen-at T, in

on the heels of impeller l mounted on its tapered end as by a hub is; de-

e present invention, with certain parts i.

tric motor (not shown). Bolted to the housing v is one side wall 9 of the pump casing, which side wall may be formed with a housing il' con-' 5 ,tainingpacking ll around the impeller shaft.

Bolted to the side wall a is the end wall I! of the 'pump casing, which contains the usual volute chamber of the pump. If desired,- the other side wall I; of the pump casing may be cast integral with the end wallit. The inlet pipe to the pump 'is shown at M. and as shown it has abolting 1 flange l5, rigid on its end, whichis bolted to the side wall it of the pump casing, as by bolts and nuts I. The discharge 'endof the volute chamber is shown at IT. Obviously the construction of the parts above described may be varied to suit the type of. pumpio which the invention is applied. 1

, Theimpellershaft projects into the interior of the pump .casing,- and the impeller i8 is sirably a bolt 2!, threaded in the end of the shaft fastens the impeller thereon. The impeller shown is of the'closed type; it"has two spaced 25 disposed in co-axial alisnment with the inlet pipe .and eye. Thefaceof the suction inlet conposegof the reduction in diameter of the eyeas compared with that of the inlet pipe is to increase the velocity of the liquid passing through theeye or the-impeller.

The eye opens to an inlet chamber 26 in'the .impellenjin which chamber the velocity of the liquid lei-decreased as it passes throughdt, and ,this slowing up of the .velocity allows the solids The heel 21 of each impellerblade is made relatively narrow and is convex or rounded off as seen in Figures 2 and 3, and merges into the inner and outer faces 28, 29 of the blades. Instead of being parallel-with the axis of the impeller,

the heel of each-blade preferably slopes at. an angle to the axis of the impeller, and the inner and outer faces of the blades, beginning at the which is mounted an impeller shaft 8,. driven 5 heel, slope from one side wall to theother for a PATENT pan I side wall ll of the casinghas a suction inlet 25 to bunch together before proceeding through the passages between the impeller bladest short distance and gradually merge into the nels formed by the side walls and blades may be.

circular or other rounded contour,.a.s is desired. The inner face 28 of eachbiade extends in a curvilinear line from the convex face of the heel, running from the curved face of the eye along a line which is non-concentric with respect to the axis of the impeller, and approaches the opposite heel to a point'approxlmately opposite the crown of said heel, whereby the cross sectional area of the passages between the heels and the leadin ends of the blades decreases to a point approximately oppositethe crown of said heel, and then continues along a curvilinear line approximately concentric with the convex face of the heel of the other blade, and then takes a curvature suitable for most efficient pumping of the liquid, the extremity of the inner face ending at the periphery of the impeller.

The outer face 29 of each blade extends from the convex face of the heel along a curved line substantially paralleling the curvature of the inner face of the tail end of the companion blade and then curves in a direction around but excentric to the axis of the impeller, and progresses towards the periphery of the impeller along a curved line best adapted for efficiently impelling the liquid. Desirably the tail end of each blade extends for some distance beyond the heel of the companion blade.

As is well upderstood, the concave inner faces of the impeller blades impart suction upon the liquid and the convex sides thereof serve to, impel the liquid from the inlet chamber of the impeller to the volute chamber of the casing. However, by reason of the shape of the forward or entering ends of the sides of the blades, the velocity of the liquid isincreased as it passes the heel of a companion blade, and the suction effect of the inner face of each blade adjacent it heel, serves to draw the liquids and solids away from the opposite heel, thereby preventing the solids from being caught thereon.

' I claim as new and desire to secure by Letters Patent:

1. A centrifugal pump casing. having a suction inlet and an impeller rotating in the casing,-said *impeller being formed with an eye and with impeller blades, means to increase the velocity of liquids passing through the eye of the impeller and means to decrease the velocity of the liquid after passing through the eye, each of said impeller blades having a leading end adjacent the eye and a trailing end at the periphery of the impeller, a convex heel at its leading end and inner and outer faces that progress from the convex heel to the periphery on curvilinear lines. the inner and outer curved faces of each blade'diverging from the convex heel to provide a thickened part beyond the heel and then convergin toward the trailing end, with the inner face of each blade substantially paralleling the convex heel and outer face of the thickened portion of the other blade to formpassages between the blades whereby the velocity. of the liquid passing through the passageway is increased across the path of travel of the heel.

2. A centrifugal pump comprising a pump casing having a suction inlet which converges toward the interior of the pump casing, an impeller rotating in said pump casing and having an eye of substantially the same diameter as the smallest diameter of the suction inlet whereby the velocity of liquids passing through the eye is increased. said impeller having an enlarged inlet chamber into which the eye opens, said impeller also having impeller blades, each of said impeller blades having a leading end adjacent the eye and a trailing end at the periphery of theimpeller, a convex heel at its leading end and inner and outer faces that progress from the convex heel to the periphery on curvilinear lines, the inner and outer curved faces of each blade diverging from the convex heel to provide a thickened part beyond the heel and then converging toward the trailing end, with the inner face ofeach blade substantially paralleling the convex heel and outer face of the thickened portion of the other blade to form passages between the blades whereby the velocity of the liquid passing through the passageway is increased across the path of travel of the heel.

WILLIAM H. LANNERT.