US2466812A - Self-priming centrifugal pump - Google Patents

Description

-April 12, 1949 o. JACOBSEN SELF-PRIMING CENTRIFUGA-L PUMP Fi led Jan. 19," 1945 INVENTOR OYSTEIN JACOBSEN 5 Sheets-Sheet 3 W frw w w 0 v ,2.

ATTORNEYS Patent ed Apr. '12, 1949 SELF-PRIMING CENTRIFUGAL PUMP Oystein Jacobsen, Montgomery County, Ohio, as-

signor to The Duriron Company, Inc., Dayton, Ohio, a corporation of New York Application January 19, 1945, Serial No. 573,546

18 Claims. 1

This invention relates to pumps and, particularly self-priming centrifugal pumps.

It is an object of the invention to provide a self priming centrifugal pump. The particular object of the invention is to provide in combination with a peripheral jet, a central jet priming mechanism, in order to reduce the time required for priming.

It is also an object to provide with the peripheral jet, means of preventing cavitation in the impeller wheel and to combine with the said peripheral jet, which is so arranged as to fill the wheel during the priming operation at. the earliest possible moment, an injector or central type of jet; the combination having the dual, advantage of providing priming fluid and of also inducing the flow of fluid from the main line into the vanes of the pump. The recirculation thus set up creates a vacuum within the suction line and decreases the'priming time.

It is a further object to provide in connection with an improved pump, an arrangement and construction in which it is possible to connect the several parts of the pump and the priming mechanism together in order to avoid any threaded portions and to permit a ready assembly and disassembly of the several parts of the pump for inspection and repair.

A further object of the invention is to prevent cavitation of the pump, thereby reducing the corrosive effect of the fluid being handled by the pump and improving the efiiciency of the pump. This is secured by the peripheral jet which is not only useful in connection with the priming of the pump, but also in increasing the efficiency of the pump during operation by reducing to a minimum any intrained air.

Referring to the drawings in detail:

Figure 1 is a vertical section through the pump and ejector mechanism of this invention and is indicated by the line |l on Figure 2 looking in the direction of the arrows;

Figure 2 is a section on the line 22 of Figure 1, looking in the direction of the arrows;

Figure 3 is a section taken on the line 33 of Figure 2 looking in the direction of the arrows;

Figure 4 is a section on the line 4-4 of Figure 2 looking in the direction of the arrows;

Figure 5 is a modified form showing a pump having a peripheral jet but no central jet.

Figure 6 is an enlarged detailed view showing the precise arrangement of the priming jets and particularly the arrangement of the center jet as associated with th pump; and

Figure 7 is a sectional line l'! of Figure 6 looking in the direction of the arrows.

Referring to the drawings in detail, I designates the drive shaft turning in the direction indicated by the arrow in Figure 1. This drive shaft is provided with a reduced diameter stem 2 having a threaded outer end 3 on which is mounted a nut 4' that is adapted to engage with the head 5. The head 5 fits snugly within the sleeve 6 of the pump collar, the collar being provided with a shoulder I for engaging with the nut 4. The left hand end of the sleeve 6 is tapered as at 8 for engaging with a correspondingly tapered surface on the shaft I. In this manner the shaft I and the sleeve 6 of the impelller are retained against one another to form a continuous shaft structure. This is accomplished without the threading of the sleeve 6 or the shoulder l, which is of advantage because these portions of the mechanism are made of noncorrosive material such as silicon bearing iron, adapted for handling corrosive fluids but machinable only with difiiculty.

Surrounding the sleeve 6 is a retaining collar 9 engaging with a packing I0 and held in position by the bolts H which are mounted in the supporting structure Ila. A grease cup I2 is provided forsupplying lubricant to the passageway l3 around th outside of the sleeve 6, one end .of the passageway being closed by the packing l5 which is held in position by the gland l4.

The sleeve 6 is also provided with a hub l 6 from which radiates a back plate l1. The front of this plate is divided by a plurality of impeller blades l8, the space between the blades l8 being designated at I9 and provides the bucket space for the impeller of the pump. The back of the plate I! is provided with ribs 20 which stiifen the impeller and also tend to pump the fluid away from the impeller journal. I

The housing I la for the packing I0 is extended into a housing for the impeller of the pump forming the left hand side of the housing as at 2i. The lower part of this casting is provided with a passageway 22 which is closed by the plate 23. The upper portion of the casting 2| extends upwardly to form the discharge passageway 24 and priming passageway 25. The throat containing the passageways 24, 25 is designated 26.

The priming passageway 25 is provided with the aperture 21 which communicates with the passageway 28 in the central jet 29 which has an ejector opening 30 which discharges into the bell mouth opening 3| leading into the impeller of the pump. The bell mouth 3| is integral with the front portion of the pump housing-designated portion of the fluid in the passageway 25 through the central jet 29, 30 into the bell mount 3|.

The retaining rings 4! and 42 are held together by the bolts 43 and serve to keep the castings 2| and 33 together as a unit to form the complete housing for the pump. Thedome casting 48 is retained by the clamping ring 44 and 45 engaging the opposing flanges 41 and 48. The rings 44 and 45 are held together by the usual bolt 49.

The casting 46 is provded with an enlarged chamber 50 within which is located guide ribs the outer edges of which are formed integrally with the casting 46 and the inner edges of which are connected to the upwardly extending tube 52. This is a discharge tube from which the fluid of the pump is discharged around the guide members 54 and out through the exit point 53 or over the lip of the tube 52 and back into the passageway 55 and then through the passageway 25 and into the jet injector tube 29.

It will be understood that it is preferred to have the combination of the central jet and the peripheral jet in order to bring about the maximum priming efiect with the minimum amount of time, but that the peripheral jet alone maybe employed. The advantage of employing them both is at least partially to fill both the volute of the pump and also the space between the blades 50 that there will be a minimum of cavitation and a maximum of fluid flow in a minimum time.

By employing the nozzle 29 and the orifice 30 to create a jet discharging into the bell mouth 3 I, it is possible to increase the efl'iciency oi the pump by substantially avoiding turbulence at the pump inlet. At the same time, the peripheral jet avoids turbulence between the blades and at least partially fllls the space therebetween with liquid in order to get the maximum pumping effect from the impeller.

It is my desire to comprehend within the scope of my claims hereinafter appended such modi- 'flcations and changes as may be necessary in order to adapt the invention to various conditions and usage.

I claim:

1. In a self priming centrifugal liquid pump, the combination of a pumping mechanism, a continuously open peripheral liquid primer jet and a continuously open central liquid primer jet.

2.-In combination in a self priming liquid pump, a pump housing, a rotor, means of conveying the discharge of the pump away from the rotor, means for continuously returning a portion of the liquid discharge to the rotor to the periphery thereof and to the center of the pump.

3. The combination of a centrifugal liquid pump, a pump housing having a suction line and a discharge line, a runner in said pump with means for enclosing the face of said runner with the exception of the inlet of said pump, means for continuously returning discharge liquid from said runner to the periphery of said pump and to the inlet of said pump in order to maintain prime on the pump.

4. In combination in a self priming liquid pump, of a pump housing comprising a suction line and a discharge line, a pump runner having blades, means to enclose said pump runner comprising a, volute housing progressively extending from a point adjacent to the runner to a point remote from the runner at which point the fluid from the runner is discharged, and means for continuously returning a portion of the discharge liquid to a point at the periphery of said blades adjacent to the departure of the fluid from the pump housing in order to maintain prime on the ump.

5. In combination in a self priming centrifugal pump, a pump housing, a runner, a discharge line from the periphery of said runner to a point within and spaced from said pump housing, means forming an enlarged chamber around the end of said discharge line to provide an exit for the main body of fluid so discharged and an exit for a portion of the fluid so discharged back to the runner, and means of conveying said fluid back to the runner at a point tangential to the runner and in a direction opposite the direction of movement of the runner whereby fluid is introduced between the blades of the runner to prime the pump.

6. In combination in a self priming liquid centrifugal pump, a pump housing, a runner, a liquid discharge line from the periphery of said runner to a point within and spaced from said pump housing, means forming an enlarged chamber around the end of said discharge line to provide an exit for the main body of liquid so discharged and an exit for a portion of the fluid so discharged back to the ruuner, means of conveying said liquid back to the runner at a point tangential to the runner and in a direction opposite the direction of movement of the runner whereby liquid is introduced between the blades of the runner to prime the pump, and means of diverting a portion of the return liquid into the center portion of said rotor whereby the cen-- ter of the pump is primed with liquid and liquid is induced to flow through the suction line of the pump.

'7. In combination, in a self priming centrifugal pump, of a pump housingcomprising a volute casing, a runner within said casing, suction line communicating with the center of said runner, a liquid discharge line communicating with the periphery of said pump adjacent the point of the maximum distance of the volute casing with respect to the periphery of the runner, means of returning a portion of the fluid liquid from said discharge line into the periphery of the pump runner between the blades thereof at a point adjacent to the point of discharge of the fluid from the runner and in a direction tangential to said runner but in a direction opposite to the movement of said runner, and means of introducing a portion of said return fluid into the center of the runner to prime the pump and to induce the flow of fluid to the suction line of the pump.

8. In a self priming centrifugal pump, an peller, a pump housing comprising a compartment for said impeller, a cover for said impeller compartment that has a centrally located Venturi nozzle adjacent to the center of the impeller, an

injection nozzle introduced adjacent the said discharge port and a return liquid discharge port for returning a portion of the discharge liquid into the impeller chamber of said pump, means for continuously returning a portion of said fluid into said injector nozzle and another portion of said fluid continuously into the periphery of said pump impeller.

9. In a self priming centrifugal pump, an impeller, a pump housing comprising a compartment for said impeller; a coverfor said impeller compartment that has a centrally located Venturi nozzle adjacent to the center of the impeller, an injection nozzle introduced adjacent the said Venturi nozzle, an enlarged chamber connected with the suction line of the pump formed in the inlet side of said housing, means forming a discharge line from the impeller compartment, means forming a chamber connected with said discharge line, said means having a main discharge port and a return discharge port for returning a portion of the discharge liquid into the impeller chamber of said pump, means of returning a portion of said fluid into said injector nozzle and another portion of said fluid into the periph cry of said pump impeller, said last mentioned discharge being directed tangentially into the periphery of the impeller of said pump between the blades of the impeller and in a direction counter to the direction of movement of the impeller.

10. In a self priming centrifugal pump, an impeller, a pump housing comprising a compartment for said impeller, a cover for said impeller compartment that has a centrally located Venturi nozzle adjacent to the center ofthe impeller, an injection nozzle introduced adjacent the said Venturi nozzle, an enlarged chamber connected with the suction line of the pump formed in the inlet side of said housing, means forming a liquid discharge line from the impeller compartment, means forming a chamber connected with said discharge line, said means having a main liquid discharge port and a return discharge port for returning a portion of the discharge liquid into the impeller chamber of said pump, means of returning a portion of said liquid into said injector nozzle and another portion of said liquid into the periphery of said pump impeller, said last mentioned discharge being directed tangentially into the periphery of the impeller of said pump between the blades of the impeller and in a direction counter to the direction of movement of the impeller,-said pump housing around said impeller being arranged in a volute form whereby the wall of the housing surrounding the impeller progressively increases in the distance from the periphery to the impeller from the point of introduction of the priming fluid into the impeller to the point of discharge of fluid from the impeller.

11. In combination, in a self priming centrifugal pump, of a casing comprising an enlarged chamber connected to a suction line, an impeller, an impeller chamber and an enlarged discharge chamber, and a liquid discharge pipe communicating from the impeller chamber to the interior of the discharge chamber in special relationship thereto, a cover for the impeller chamber comprising a Venturi passageway, a nozzle mounted in the first mentioned suction chamber adjacent to said Venturi passageway for central injection of priming liquid into the center of the impeller, means for continuously returning liquid from the enlarged discharge chamber to said nozzle and continuously to the periphery of the impeller of the pump whereby the combined effect is accomplished of priming the pump and inducing the flow of liquid from the suction line into the pump 6 housing and impeller in order to accelerate putting the pump into effective operation in the minimum period of time.

12. In a centrifugal pump for liquid; an impeller; an impeller chamber having a central inlet, a volute passage around the periphery of said impeller and a fluid discharge outlet communicating with the largest portion of said volute; means for continuously diverting a portion of the liquid discharge of said pump to the periphery of said impeller at the narrowest portion of said volute; and means for continuously returning another portion of said discharge to said central inlet in the form of a jet; whereby to prevent cavitation in said pump and to prime the same.

13. A self priming liquid pump comprising a pump housing including a single discharge conduit, a rotor, means for conveying the discharge of the pump from the rotor into said conduit, and means comprising a return passageway within the single discharge conduit for returning a portion of the liquid discharge to the periphery of the pump rotor, the area of the return passage way being so small as compared with the area of the discharge passageway as to be accommodated by the normal size of discharge conduit.

14. In combination in a self priming liquid pump, a pump housing having a suction line and a discharge line, a runner in said pump with means for enclosing the face of said runner with the exception of the inlet of said pump, said discharge line comprising a single outgoing conduit and partition means in said conduit for return-,-

ing discharge liquid to the periphery of said runner, the area of the liquid return portion of the conduit being so small as compared with the area of the discharge portion of the conduit as to permit both portions to be accommodated in a conduit of the normal size required by the discharge of the pump.

15. A centrifugal pump comprising a casing having an impeller therein and an eye at the center for admitting fluid to said casing, a discharge port at the periphery of the casing, a neck secured to the casing at said port, and a partition which extends within the neck throughout only a portion thereof to form two passageways which communicate with one another at a position remote from said port, one of said passageways constituting a continuation of said discharge port and the other passageway constituting a means for conveying fluid through said neck back to the impeller at a point tangential to the impeller, said partition being of such thickness only as to withstand the pressure of the fluids passing through the neck whereby the size of the neck .in the transverse direction is no greater than would be required for the normal discharge of the pump.

16. A priming pump comprising a casing having an impeller therein and an eye at the center for admitting fluid to said casing, a discharge port at the periphery of the casing, a neck secured to the casing at said port, and a partition which extends within the neck throughout only a portion thereof to form two passageways which communicate with one another at a position remote from said port, one of said passageways constituting a continuation of said discharge port and the other passageway constituting a means for conveying fluid through said neck back to the impeller at a point tangential to the impeller and in a direction opposite the direction of movement of the impeller whereby fluid is introduced becan:

having an impeller therein and an opening at the N center top admitting fluid to said casing, a pair of openings at the periphery of said casing, and a single conduit having a partition to form two 10 passageways .which communicate respectively with said openings and with one another at the position remote from the openings, one of said passageways serving to receive fluid discharged ing to return a portion of the discharge fluid back to the impeller through the other of said openings, said partition being of such thickness only as to withstand the pressure of the fluids passing through the neck whereby the size of 20 the neck in the transverse direction is no greater than would be required for the normal discharge of the pump.

18. A centrifugal pump comprising a casing having an impeller therein and an opening at the center for admitting fluid to said casing, a pair of openings at the periphery of said casing and g a neck extending outwardly from the casing first in a tangential direction with respect to the imthrough one of said openings and the other serv- 15 8 peller and then in a radial direction, a pair of passageways within the neck and having contours coincident with the contour of the neck, said passageways communicating at one end with a pair of openings at the periphery of the caslng'and at the other end communicating with one another whereby one of the passageways is pointed in a direction as readily to receive fluid from the impeller and discharged through one of said openings and the other is pointed in a direction to return a portion of the discharged fluid back to the impeller through the otherof said openings in a direction opposite to the direction of movement of the impeller.

OYSTEIN JACOBSEN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENrs Nelson May 14, 1946

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