US2478941A

US2478941A - Centrifugal pump

Info

Publication number: US2478941A
Application number: US720037A
Authority: US
Inventors: Jack E Piccardo
Original assignee: SHASTA PUMP Co
Current assignee: SHASTA PUMP Co
Priority date: 1947-01-03
Filing date: 1947-01-03
Publication date: 1949-08-16
Anticipated expiration: 1966-08-16

Description

Aug. 16, 1949. J. E. PICCARDO CBNTRIFUGAL PUIP 4 Sheets-Sheet 1 Filed Jan. 3, 194'! INVENTOR. JACK E P/CCflFDO Aug. '16, 1949. E; PICCAR O 2,478,941

OENTRIFUGAL PUMP Filed Jan. 3, 1947 4 Sheets-Sheet 2 j INVENTQR. /Z JACK E. P/CC/JEDO Aug. 16, 1949. J. E. PICCARDO cwmruen rumr 4- Shee tS-Sheei. 3

Filed Jan. s, '1947 INVENTOR.

F l E E T JACK 5. P/CCAEPO v /02 BY Aug. 16, 1949. J. E. PICCARDO CENTBIFUGAL PUMP Filed Jan. 3, 1947 4 Sheets-Sheet 4 /2/ I 5 Fl 5-55 K43 mmvron. JACK E. P/ccA/200 I I 01 I z going, will Patented Aug. 16, 1949 Jack E.

Shasta Pump fornia Piccardo, Oakland, Calif., .aasignor to Company, a corporation of Call- Application January 3, 1947, Serial No. 720,087

19 Claims.

The invention relates to'centrifugal pumps and more particularly to that class of relatively small size well pumps used for domestic pressure systems and farm irrigational purposes wherein the pump is adapted for vertical mounting directly over the well.

An object of the present invention is to provide a pump of the character described wherein the several parts thereof are so designed, arranged and constructed as to permit the interchangeability of certain of the parts to produce a plurality of pump sizes such as one-third, onehalf, three-fourths, one H. P., etc., and a plurality of pump types such as shallow well, deep well, and single and multiple stages.

Another object of the invention is to provide a centrifugal pump assembly which is designed for a direct connection of the pump motor to the impeller housing thereby minimizing the distance between the motor shaft bearing and the impeller, permitting a direct mounting of the impeller on the motor shaft, and maintaining positive and precise alignment and concentricity of the motor shaft, impeller and the impeller chamher.

A further object is to provide a centrifugal pump of the character described which is constructed of a housing having seamless, imperforate and generally cylindrical sides extending from the pump motor to a point substantially below the impeller and being designed for receipt of various sizes and types of insert members to provide in combination therewith a plurality of sizes and types of pumps.

Still another object of the invention is to provide a centrifugal pump of the character above which consists of a minimum number of ruggedly formed parts which are designed for ready production with lowered manufacturing and. machining cost and for quick and easy assembly, and which will afford improved and maximum operating efliciency over a long period of use.

Yet another object of the invention is to provide a centrifugal pump of the character de- I scribed in which the pump and electric motor therefor are assembled in a single compact and streamlined, unit which is of reduced weight and at the same time affords a substantially improved appearance.

The invention possesses other objects and features of advantage, some of which, with the forebe set forth in the following description of the preferred form of the invention which is illustrated in the drawings accompanying and forming part of the specification. It is to be understood, however, that variations in the showing made by the said drawings and description may be adopted within the scope of the invention as set forth in the claim.

Referring to said drawings:

Figure 1 shows in side elevation a centrifugal pump constructed in accordance with the present invention in combination with a water pressure system.

Figure 2 is a vertical sectional view of the pump illustrated in Figure 1, the section being taken substantially on the plane of line 2-4 of Figure 3.

Figure 3 is a plan sectional view of the pump taken substantially on the plane of line 3+3 of Figure 2. I

Figure 4 is a plan sectional view of the pump taken substantially on the plane of line 4-4 as shown in Figure 2. 4

Figure 5 is a vertical sectional view similar to Figure 2, but showing another form of the pump.

Figure 6 is a vertical sectional view similar to Figure 5 but showing still another form of the As hereinbefore noted, the pump of the present invention is designed and constructed for the incorporation ina single centrifugal pump housing of various sizes and types of insert members adapting the same pump motorand housing to varying installation requirements. Heretofore, centrifugal pump units have been limited each to a particular size of motor and pump size and type. For example, a one-quarter horsepower motor combined with a shallow well, single stage pump. The centrifugal pump assembly incorporating the present invention makes it possible to use a given size standard electric motor and a given size pump casing for a plurality of well installations, including both single and multi-stage, shallow and deep'well conditions, by selective assembly with such motor and casing various sizes and types of impellers and insert members.

In Figure 1 of the drawing, a single stage shallow well centrifugal pump constructed in accordance with the' present invention is shown operatively connected in a fluid pressure and storage system, including the pump ii, an intake conduit 12 connected thereto and tapping a source of fluid for supply to the system, and a discharge conduit l3 connecting the pump to a fluid storage tank ll. A pressure responsive switch is connected in the discharge conduit reflects pressure variations in the storage tank to intermittently actuate and discontinue operation of the pump II to maintain the water supply and pressure in the tank It within a predetermined range.

In practice, the pump is designed for mounting directly over a well and upon the well casing with the well pipe |2 connected to and depending from the bottom of the pump. A foot valve and strainer I6 is customarily provided at the lower end of the well pipe to admit water to the pipe during operation of the pump and functions as a check valve automatically to close on stopping of the pump to maintain the water in the system i or subsequent pump operation without priming. When priming is necessary, an upturned elbow fitting i may be provided as here shown in the standpipe |8 leading to the pressure switch for entering water tothe system. The fitting I1 is normally closed by a plug 20. An air volume control valve 2| is shown on the tank l4 and is connected by an air line 22 to the pump for maintaining in the tank a head or cushion of compressed air which serves to retard the drop in pressure in the tank as water is drawn therefrom.

1 The pump comprises an electric motor 23 having a shaft 24, and a seamless bell shaped impeller casing 26 having the top wall 21 thereof abutting and secured to the lower end 28 of the motor adjacent shaft 24. Preferably the casing 26 is aflixed to the end of the motor by a means of bolts 29 traversing an upper flange 32 provided onthe top wall 21 of the casing and tapped into the motor housing. A reduced step recessed portion 33 of the casing below the top flange 32 of a smaller diameter than the flange afiords access to the bolts 29 from the exterior of the pump, permitting detachment of the motor from the impeller casing without the necessity of access to the interior of the casing. Radially extending webs 34 intersect and reinforce the stepped portion 33 and aid in maintaining a positive alignment between the casing and the motor 23 mounted thereon. Suitably secured to the free end of motor shaft 24 as by threaded engagement therewith is an impeller 36, preferably formed of non-ferrous material and dynamically balanced for vibration free operation 'by the motor 23.

So much of said pump unit as has heretofore been described, including the electric motor and housing therefor, the seamless impeller casing 26 attached thereto, and impeller 36 secured to and rotatable with motor shaft 24, comprises a selfcontained and standard portion of the complete pump which is adaptable to a variety of well conditions, as shallow and deep well installations, by the substitution in the impeller casing 26 of various types of impeller inserts as will be hereinafter described.

As shown in Figures 1, 2, 3 and 4, the basic pump parts-the motor 23, impeller casing 26 and the impeller 36 are operatively connected for a shallow well installation to a shallow well impeller insert 31. Insert 31 is of generally cylin-' drical form conforming to and fitting within the open, belled end 38 of casing 26. A peripheral flange 39 provided on a bottom plate like portion 4| of the insert seats against an inturned flange 42 adjacent the lower end 36 of casing 26, and the insert is preferably positioned within the casing by means of a plurality of bolts 43 intersecting

flanges

39 and 42 and threadably engaged in the former to alTord access to the bolt heads exteriorally of the casing 26. By means of the exterior bolts 43 and the step construction of the insert 31 and the interior of casing 26, free dis-, assembly of the casing from the insert is permitted without the necessity of access to the interior of the casing or to the underside of the insert. This latter feature is highly desirable vided in the when the insert is mounted on a well casing and the underside of the insert is relatively nonacoessible for assembly or disassembly.

As an aid to mounting the base portion 4| of the insert directly upon the well casing so as to support the pump as is intended and also to support the connected suction pipe l2, there is preferably formed on the underside of the base 4|, a plurality of depending generally radially extending ribs 40 which extend below the plane of the lower end 38 of the casing so as to form the bottom support for the unit. These ribs also serve to reenforce the base of the insert so that it will be sufliciently strong to carry the weight.

Extending upwardly centrally of the base porthe insert is a tubular portion 44 which flares outwardly at its upper end to define a saucer-shaped top portion 46 which underlies the impeller 36. The peripheral edge 41 of the portion 46 is upturned to engage and seal against an internal annular flange 49 provided in the casing by reason of and at the base of the reduced portion 33. Sealing gaskets 5| and 52 may be provided between the

abutting flanges

39 and 42 and between the top edge 41 and flange 49 so as to provide a simultaneous sealing oil. of these engaging surfaces upon drawing of the insert into the casing by means of bolts 43. As will be noted from Figure 2 of the drawing, the top portion 46 of the insert member and the side and top wall of the casing above'the flange 49 define a top impeller chamber 53.

With reference to Figure 2, it will be noted that the pipe i2 is threaded into an intake fitting 56 formed in the base 4| of the insert and which opens into the tubular portion 44 eccentrically of the pump axis-see Figure 4. The tubular portion 44 is joined to the top wall 46 of the insert in a central vertical throat 51 which receives the inlet eye 58 of the impeller 36. Fluid is thus admitted into the hollow interior of and is discharged radially therefrom through peripheral and eircumferentially extending oriflces 59 in the rim 6| thereof. It will be noted that the rim 6| of the impeller is arranged in annular juxtaposition to the upturned top edge 41 of the insert member. As an important feature of the present construction, and as best seen in Figures 2 and 3, the portion 41 of the insert member is formed of a pair of spiral

involute ribs

62 and 63, which form an involute discharge the impeller, and provide ibetween of the casing around the tubular insert. The casing sidewall is discharge outlet 61 communicating with the portion 44 of the chamber 66 and to which the discharge conduit mounted for rotation with the motor shaft 24 I and supported around the shaft by means of a ring carrier 69 in turn supported on a helical spring 1| mounted on an end face of a hub 12 on the impeller. The sealing ring 68 is resiliently pressed by spring 1| against a stationary sealing ring 13 sealed in the shaft opening 14 protop wall 21 of the casing. such ring the impeller 1 ll being so sealed by a compressible gasket I8. Preferably the engaging sealing rings 88 and 13 are made of dissimilar materials such as bronze and carbon.

Sealing ring 58 rotating with shaft 24 and the impeller rides upon the opposed face of stationary sealing ring 13 and the engaging surfaces thereof are lubricated by means of the fluid in the impeller chamber. A slinger I1 is positioned on the motor shaft exterior of the top wall 21 of Venturi means-functioning as an aspirator for lifting the well fluid out of pipe l2 and increasing the fluid pressure at the intake of the impeller.

This means thus functions built in as a booster pump in the line to the impeller. A portion of the high pressure discharge fluid is passed back through the nozzle and Venturi means in a. re-

generative type cycle. With reference to the drawings, it will be noted that the tubular portion 44 of the insert is formed as a boxlike section having a generally rectangular upstanding wall 19,

as viewed in plan, extending between the base plate 4| and the top plate 46 to define an enclosed chamber 8|. This wall 19 forms the inner boundary of the fluid collecting chamber 66 above noted. One end 80 of this wall is formed with an opening 82 in which is fitted a nozzle 84 arranged with the enlarged intake end 85 at the fluid collecting chamber 66 and the reduced discharge end 88 extending and pointing into the chamber 8| directly over the pump intake opening 56 provided in the base plate 4| of the insert. Spaced axially of the nozzle 84 in the chamber 8| is an axially concentric shoulder 81 formed in the walls of the chamber and which supports one end of a Venturi tube 88 aligned with the nozzle, the tube being preferably supported by a pressed fit in the shoulder 81, Thus fluid under pressure is directed through the nozzle into the Venturi tube creating a low pressure chamber around the nozzle at the receiving end of the Venturi tube which draws the well fluid up out of the pump intake opening. The velocity energy of the fluid discharged from the nozzle is converted into pressure energy-by the Venturi tube, thus raising the fluid pressure in the chamber 8| and at the throat 51 leading to the impeller intake 58.

On starting the pump, fluid is immediately evacuated outof chamber 8| by the impeller and until this fluid is replaced by the regenerative cycle above described there is a'low pressure cOndition obtaining in the chamber 8|. Advantage is taken of this condition to draw a charge of air into the pump for subsequent passage with the water into the tank to constantly recharge on each starting operation of the pump the air cushion at the top of the tank. With reference to Figure 2 of the drawing, it will be noted that an air intake passage 89 is provided through the base portion 4| of the insert communicating with chamber 8|. valve 9| is connected to this passage 89 exteriorly of the pump and in the air line 22 above described. Air is admitted to the line 22 from the atmosphere through the valve 2| which is opened and closed charger, (not shown).

A one-way air check or snifter by a float (not shown) mounted in the tank l4. When the air cushion at the top of the tank is reduced below a desired amount, the float rising with the water in the tank opens the valve 2| to communicate line 22 with the atmosphere, thereby admitting air through the snifter valve 9| on subsequent starting-up of the pump. The valve 2| and its associated float mechanism is well known and commonly used inthe art, and therefore not shown or described in detail in this application. The common type of valve 2| is provided with a tank communicating fitting for receipt of a dial pressure gauge 92, for indicating the pressure in the tank.

Assuming the fluid flow and storage system shown in Figure 1 to be put into initial operation, the pump is primed by introducing fluid through the fitting H at a high point in the system, permitting the interior of the pump to be completely filled. As an aid in evacuating any air which might be trapped in the system, an air valve 93 is desirably positioned in the side wall of the casing at the top chamber 53, bleeding air from the highest internal cavity, and the air valve is permitted to remain open with fluid flows therefrom. After initiation of the pumping operation, as the desired fluid level and pressure are reached in the storage tank, the pressure responsive means I5 will shut off the pump motor, and the fluid in the system will fill the same and be held therein by operation of the foot valve I6, maintaining the system in a condition for instantaneous operation under the control of the pressure means as the demands upon the fluid storage tank cause a loss in fluid and pressure therein.

As shown in Figure 5 for adapting the pump motor and impeller casing as shown in Figures 1 to 4 to deep well installations, a new impeller insert 31' is provided. This insert is constructed and mounted similarly to insert 31 above described except that the box-like center section and the nozzle and Venturi means are deleted.

Fluid is admitted through an axially arranged opening 56 in the base plate 4| of the insert and passes upwardly through a hollow tubular center portion 44' to the intake of the impeller. In this form of the pump a second opening Jill is provided in the base plate 4| of the insert, which communicates with the fluid collecting chamber 66 and is arranged for connection to a fluid pressure pipe I02 which extends down into the well parallel to intake pipe l2 to a jet eductor assembly (not shown) provided in the well below the mean fluid level therein, This jet eductor is commonly known in the art, and therefor not shown here, but functions to elevate the water in the intake conduit l2 to within the operating level of the pump impeller. A pump discharge passage 61' is provided on the casing in communication with the fluid collection chamber 66' above described for delivery of the water from the pump to a storage tank or other exterior disposition. In this embodiment, the base plate 4| of the insert member is provided with an auxiliary water passage I03 which opens into the central intake passage of the pump and is adapted for connection by conduit I04 to a deep well pump air- This form of the pump may be used if desired as 'a shallow well pump by simply plugging the opening |0|. In such case, of course, the auxiliary booster nozzle and Venturi arrangement in the first described embodiment, would not be utilized, as where the intake water level or pressure is such as not to require the booster feature.

' formed integrally with the manner as described in the emb In Figure 6.01 the drawing there is shown an impeller and insert construction for a multi-stage pump. As shown in this figure, the pump motor 23" and impeller casing 26" are associated with a. two piece insert 31" composed of a base plate 4i" and an intermediate insert I05, accommodating a dual impeller construction. The bottom plate II" is ailixed to the casing by means of a plurality of bolts 43" as in the first described embodiment. Bottom plate 46" is providedw'ith a concave upper surface portion I06 concentric to an intake passage 56" provided in the base plate ll centrally thereof for connection to. conduit I2". Positioned and supported between the base plate 4i" and the upper recessed flange 49" of the casing is the intermediate insert member I05 which is of a generally cylindrical form having a top wall I08 and a bottom wall I09, and intermediate there between a chamber HI. An imis afiixed to the motor shaft M" as in peller 3B" the previous embodiments, but is here formed with a depending threaded extension IIZ projecting through a passage H3 in the top wall I00 of the intermediate insert. Impeller 36" is positioned within an upper impeller chamber 53" defined by the top wall 21" of the casing, the side walls thereof, and the top wall I08 of the intermediate insert. Involutes 62" and 63 are top I08 in the same form and manner as are the

involutes

62 and 63 of the first described embodiment. A second impeller H4 is secured to the extension II2 of impeller 36", and impeller I I4 is positioned within a lower impeller chamber II 6 defined by the bottom wall I09 of the intermediate insert, and the top surface" I06 of the base 4!. I

A second pair of involutes H8 and 9 are provided'integral with the bottom I09 of the intermediate insert adjacent the periphery. of impeller H4 and within anannular ring I20 for the collection and directioning of fluid discharged by the impeller from chamber H6 into chamber III. Fluid entering the pump assembly through the central opening 56" passes into impeller H4 centrally thereof, is discharged into chamber I I6, thence through involutes H8 and H9 into chamber I I I, from where the fluid is picked up by the upper impeller 36" and discharged through in-- volutes 62" and 63" into a fluid collecting chamber 66" defined between the pump casing and the intermediate insert I05. A discharge fitting 61" is provided .on the casing 26" in communi-- cation with the collection chamber 66" as in the I above described embodiments.

As shown in Figure 6, a second opening I2I may be provided in the insert base I I for connection to a sub-fluid level ejector assembly in the same odiment shown in Figure 5. This opening I 2| may be closed 011 by a suitable plug where the jet eductor is not used as has been hereinbefore noted. Also in this embodiment an auxiliary water passage I22 is provided inthe base 4!? for connection to' an external air charger'in the scribed in..the embodiment illustrated in Figure 5.

earing is required. This applies to both the s ingle stage and themultiplev same manner as dempact unit wherein a standard shaft length impeller other than the i The compact, short coupled, conthe elimination of all bearings exelectric motor, greatly facilitates assembly of the pump, practically ation and promotes smooth, quiet operation. It will also be noted that by reason of the features disclosed a two stage pump may be provided within the same dimensions as a sinle stage pump.

While the foregoing embodiments have been described as combinations with a given size of motor and pump casing, variouspump capacities may be produced by combining with a given size housing, different size inserts and/or impellers and electric motors. Thus it is practical to use the same housing for A 35% and 1 horsepower pumps, shallow and deep well, and single and multi-stage types to produce well over twenty different type units.

I claim:

- 1. In a pump of the character described in com bination, an electric motor having a housing and drive shaft extending from one end thereof, an

. impeller fixed to said shaft, a seamless casing 25 surrounding said impeller and having a closed end secured to said motor housing end and an annular side wall extending from said closed end 'to an opposite open end of said casing, and a member connected to said casing and closing the open end thereof and extending interiorly of said casing to define with said closed casing end an impeller chamber surrounding said impeller, said member and casing being provided with inlet and discharge openings communicating with said impeller and chamber respectively.

2. In a centrifugal pump, a casing having a generally cylindrical seamless side wall and top wall and formed with an open bottom, said side wall having an internal flange at substantially right angles to the longitudinal axi of the casing'and exposed from the open bottom of the casing, said casing being provided with .a second annular flange adjacent theopen end thereof and within the confines of said side wall, a bottom insert member having portions in sealed engagement with said flanges and defining with said top wall an impeller chamber and defining with said side wall an annular fluid collecting chamber; an impeller mounted for rotation in said. impeller chamber, and inlet and discharge means communicating with said impeller and said. collecting chamber respectively. V

3. In a centrifugal pump,

stage units.

struction and terior of the alignment and eliminates vibr and bottom such flangeat substantially rl longitudinal axis ofthe casing go ttom of the casing,

with the plane of ght-angles to the -open -end thereof, an impeller mounted within said casing adjacent said first flange,a bottom insert member having upper and lower portion in 5 sealed engagement with said flanges, involutes ber,'said insert member defining with said side well an annularfluid collecting chamber communicating with said first chamber, and inlet and discharge means'connected to-said impeller and said second chamber respectively.

' 4. A centrifugal pump comprising. a bell shaped housing-having an. internal annular flange in- 7d termediate its length and an open bottom end,

an impeller mounted for rotation in said housing adiacent said flange, a bottom closure memher for said housing including a base portion extending across the open bottom of said housing and a longitudinally spaced portion surrounding said impeller and engaged with said flange, in-' volute vanes provided at the engaging surfaces of said longitudinally spaced portion and said flange surrounding said impeller and defining a discharge chamber therefor, and inlet and discharge means communicating with said impeller centrally thereof and with said impeller discharge chamber.

5. A centrifugal pump as characterized in claim 4 wherein said inlet means is provided in said first named portion of said closure member in the form of a fitting adapted for receipt of the pump suction pipe, and wherein said bottom closure member is formed with an intake passage extending from said fitting to said impeller centrally of the impeller.

6. A centrifugal pump comprising, a one piece bell shaped housing having an openbottom end, and an impeller mounted for rotation in said housing about a vertical axis, a bottom closure member for said housing including a plate like portion extending across the open bottom of said housing and an elevated portion surrounding said impeller and defining therewith and with said housing an impeller discharge chamber, said closure member being formed between said portions with a fluid chamber havin an inlet passage con= nected to said first named chamber and a discharge passage connected to said impeller centrally thereof, a Venturi tube mounted in said second named chamber in alignment with said inlet passage, a nozzle mounted in said inlet passage in alignment with said Venturi tube, the bottom portion of said closure member having a pump inlet communicating with said second named chamber and said Venturi tube, said housing being formed with a pump discharge passage communicating with said first named chamber.

7. A centrifugal pump comprising a bell shaped housing having an open bottom end, an impeller mounted for rotation in said housing about a vertical axis, a closure member for said housing including a base plate portion extendin across the open-end bottom of said housing and secured thereto and upstanding walls surmounted by a top portion underlying and extending around said impeller to define therewith and with said housing an impeller discharge chamber, the base and walls and surmounted portion of said 010- sure member defining a fluid chamber between said portions, inlet means for said second chamber communicating with said first chamber, discharge means for said second chamber communicating with said impeller centrally thereof, nozzle and Venturi means mounted between said inlet and discharge means for said second chamber, said base portion of said closure member being formed with a pump inlet opening communicating with said nozzle and Venturi means, said housing being formed with 'a pump discharge passage communicating with said first named chamber.

8. A centrifugal pump as characterized in claim '7 and formed with an air inlet valve communicating with said second named chamber at the discharge side of said nozzle and Venturimeans.

9. A centrifugal pump comprising a bell shaped housing having a top wall and an annular bottom flange and a second annular flange intermediate said bottom flange and top wall, an elecmember having a hollow upstanding centra1portion providing the pump inlet passage to said impeller centrally thereof and surmounted dish shaped portion underlying and surrounding said impeller and sealed to said intermediate flange to deflne with said housing an impeller discharge chamber, the upper extremity of said dish shaped portion being formed with involute vanes to permit discharge of fluid from said discharge chamber, said insert member providing with said housing a, fluid collecting chamber surrounding the central portion of said insert member, said housing being provided with pump discharge passage communicating with said last named chamber.

10. A centrifugal pump as characterized in claim 9 wherein said base portion of said insert member is formed with a discharge passage com- 30 municating with said fluid collecting chamber for connection to an injector means mounted in a well.

11. A centrifugal pump comprising a bell shaped housing having a top wall and an annular bottom flange and a second annular flange intermediate said bottom flange and top wall, an electric motor mounted with one end thereof upon said top wall and provided with a drive shaft extending through said top wall substantially axially thereof, an impeller mounted on said shaft for rotation within said housing below said intermediate flange, thus defining a top cham-' her in" said housing about said shaft, sealing means mounted in said top chamber about said shaft for sealing of! said top chamber along said shaft, a bottom insert member having a platelike portion extending across the open end of said housing and sealed to said bottom flange, a second impeller depending from and secured to said first impeller for rotation therewith, a secand insert member mounted upon said first insert member and having the upper end in engagement with said intermediate flange, said second insert member cooperating with said first insert chambers around said impellers and a passage connecting the discharge chamber of said second impeller to the inlet of said first impeller, said platelike portion of saidbottom insert member 00 being formed with a pump inlet passage communicating with the intake of said second impeller.

12. A centrifugal pump comprising, a bell shape'd housing having an open bottom end, a

plurality of impellers mounted within said housing for joint rotation about a vertical central axis, a base closure member extending across the bottom of said housing and formed withja pump inlet opening communicating with the lower of said impellers centrally thereof, a member mounted within said housing in engagement with said closure member and said housing and surrounding said impellers to provide discharge chambers therefor and further providing communication between the discharge passage of said member and said housing to define discharge 13. A centrifugal pump as. characterized in.

claim 12 wherein said closure member is formed with an eductor connecting passage communicating with said fluid collecting chamber.

14. A'pump of the character described coma prising, an electric motor having a housing and an end flange and a drive shaft extending axially from said end flange, a bell shaped casing having a closed end secured to said motor flange and formed with a central opening for admitting said shaft into the interior of said casing, said casing having an annular side wall extending from said closed end and terminating in an open end opposite to said closed end, a closure memberfor said housing attached to the open end thereof and having a portion projecting interiorly of said housing and engaging said side wall to define with said closed end a pump impeller chamber and defining with said side wall a discharge chamber communicated with said impellerch'amber, an tation in said impeller chamber and securedto said motor shaft, said closure member being formed with an inlet opening communicating with said impeller and said casing sidewall being formed with a discharge opening communicating with said discharge chamber.

, 15. A centrifugal pump comprising, a bell shaped housing having a closed end and a seamsaid housing across the open end thereof and extending interiorly thereof to define with said closed end an impeller chamber and to define with said side wall a discharge chamber, a drive shaft extending through the centrally of said impeller chamber, and an impeller mounted for rotation in said impeller chamber and secured on said shaft, said closure member and said side wall being formed with inlet and discharge openings communicating with ing the open end thereof and extending interiorly to define with said closed end an impeller chamber provided with a centrally arranged inlet passage and a peripheral discharge passage, a drive shaft extending through said closed end centrally of said chamber, and an impeller mounted on said shaft in said chamber, said closure member and saidhousing side wall being formed with inlet and discharge openings communicating with said inlet sages respectively.

17. A centrifugal pump comprising, a housing having a closed end and an annular side wall extending therefrom to an open end of said housing,

closed end of said housingimpeller mounted for rosaid side wall being formed with an interior annular shoulder intermediate said ends, an impeller mounted for rotation in said housing adjacent chamber between said extremity and said closed end of said casing, said closure member providing an inlet and exposed from closure member extending across and sealing the open end of said casing and having an interiorly extending portion in sealed engagement with said shoulder and defining with said end wall an impeller chamber with said impeller and said collecting chamber respectively.

19. A centrifugal pump comprising, a housing having an end wall and annular shoulder between said end wall and open end, a drive shaft extending through said end wall substantially centrally thereof, an impeller mounted on said shaft for rotation within said housing adjacent said shoulder and defining between said impeller and end wall 'an end chamber in said housing about said shaft, rotary sealing means carried by said shaft and end wall within said end chamber for sealing off said end chamber along said shaft, a closure member connected to said housing and sealing the open end eof and having a portion extending interiorly into sealing engagement with said shoulder and into surrounding relation to said impeller to provide a discharge chamber therefor, said closure member being formed with an inlet passage communicating with said impeller centrally thereof, and said housing side wall being formed with a discharge passage communicating with said impeller chamber.

JACK E. PICCARDO.

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

UNITED STATES PATENTS