US2639671A

US2639671A - Self-priming centrifugal pump unit for liquid dispensing apparatus

Info

Publication number: US2639671A
Application number: US120797A
Authority: US
Inventors: Wagner Bernard
Original assignee: Gulf Oil Corp
Current assignee: Gulf Oil Corp
Priority date: 1949-10-11
Filing date: 1949-10-11
Publication date: 1953-05-26
Anticipated expiration: 1970-05-26

Description

May 26, 1953 Y B. WAGNER 2,639,671

SELF-PRIMING CENTRIFUGAL PUMP UNIT FOR LIQUID DISPENSING APPARATUS Filed 00%.. 11, 1949 6 Sheets-Sheet l i i i 2- 7",??? 2.

40 O I v I INVENTOR. 57 BERNfiR A NER K 1 BY 41 m J h"v 56 I A %u ATTORNEY May 26, 1953 Filed Oct. 11, 1949 B. WA SELF-PRIMING CENTRI FOR LIQUID DISPENSING APPARATUS GNER FUGAL PUMP UNIT 6 Sheets-Sheet 2 INVENTOR.

. gg mwm WAGNER y 6, 1953 B. WAGNER 2,639,671

SELF-PRIMING CENTRIFUGAL PUMP UNIT FOR LIQUID DISPENSING APPARATUS Filed Oct. 11, 1949 6 Sheets-Sheet 4 AIR EXHAUST PUMP UNIT PRESSURE CHECK wave Pnmmkv CHAMBER FLO/l T RECIQCULA TING VAL VE INLET O l/TL ET luvs zszsws CHAMBER IFFl/SER can/155R srnA/NER ET RETURN LINE 7 sucT/O/v LINE ,i A v 1:; A V AQEM 54 I V I \(fl\\ I N V EN TOR. ERNPQRD AGNER May 26, 1953 B. WAGNER SELF-PRIMING CENTRIFUGAL PUMP UNIT FOR LIQUID DISPENSING APPARATUS 6 Sheets-Sheet 5 Filed Oct. 11, 1949 INVENTOR. ERN RP N ATTORNEY May 26, 1953 B. WAGNER w SELF-PRIMING CENTRIFUGAL PUMP UNIT FOR LIQUID DISPENSING APPARATUS 6 Sheets-Sheet 6 Filed Oct. 11, 1949 JNVENTOR. ERNfiRD WA swim ATTbRNL-Y Patented May 26, 1953 UNITED" S QF SELF-PRIM-ING CENTRIFUGALL PUMPQ'UNIT. FOR. LIQUID DISPENSING APPARATUS Bernard Wagner, Grafton, Pa assignonsitorGiulfii Oil Corporation,Pittsburgh, Pa., a corporation of Pennsylvania I Applicationoctoberll, 1949; Serial No. 120,797

5 Claims.-

:Ihis invention relates to a self-priming cen trifugal pumpiunit for liquid dispensing apparams, and more particularly to a pump unit which is advantageouslyadapted to perform the pumpingfun'ction'in a gasoline dispensing system and to ,deliver the gasoline. to ameter free'irom air and vapor.

The principal components of the usualgasoline dispensing system comprise an underground rese ervoir having arcomiuitv containing a .checkvalve leading therefrom to awpump, a motor to drive the pump, an air eliminator to separate air from thepnmped-gasoline, av meter throughvvhich the gasolinefrom the ,air eliminator is forcedfunder pressure, a computer having a driven connec.

tion with the meter, and a dispensing hose con-- necting with the discharge. from-the meter and containing an outlet dispensing valve. It is customary practice in suchdisp'ensing systems to employ. rotary positive displacement type pumps the. high pressures'whichahey are capable of buildingup, it is necessary to employ-therewith aby-pass line from the outlet to the suction side" of the pump to b'y-pass 'gasolinewhile the outlet valve. inthe dispensing hose is closed and the 3 pump in operation. This'characteristi'c. of'cone struction results from the common practice of operating the pump to develop pressure before the dispensing valve is openedandafter it is closed'following a dispensingioperation. We're itnotior the by-pass, if the. dispensing. valve were closed'ivith the pump, running, the pres.-

su'redeveldped Would'eith'er stop the'pump, or

It is also necessaryto' cause serious breakage. include in the icy-pass line a check valve which is designed to permit'the by-pass of gasoline when. the dispensing valve is closed and to out off" the .by-pass flow. when the dispensing valve is opened... Thedisadvantages otsuch an arrangement are many. From the economic stand-point,.

additional. power is consumed 'to pump the gasoline through the-by pass and by-pass valve. Furthermore, such construction adds to the expense A ofany gasoline pump installation. In addition,

failureoi the by-pass valvewill stall 'the'motoror otherwise result in serious damage to" the entire dispensing system.

This therefore apparent why many attempts I have been made-to'find a practical substitute for the rotary positive displacement pump; 'ingasoline dispensing systems." The use of centrifugal type pumps has been proposed? since centrifugal pumps ofie'r certain"advantagesover the-rotary to perform the pumping operation. However, due to the positive-action'of these pumps andpositivedi'splacement type pump for such a purpose; Prhaps most "significant is the fact that:

no. b'y-pass connection-need be employed withcentrifugal-ipu1nps,-' due to the characteristic of centrifugal pump impellers which enables :them toidle or slipwhil'e the dispensing valveis closed,

Without building up serious pressures on the discharge-side-of thepumps. When such a conditionexists in 'a' centrifugalpump, that *is, when 1 the dispensing valve is -closed the power consumed by=the pump is considerably-less than that consumed when the dispensing'valve is open and the pump ispumpirig underfull load. Rotary positive displacement type pumps-arenot so ad- 'vantageous-lv adapted. Moreover, a--centrifugal pump is oneof-th'e most economical and eiiicient types of devices "for-*pumping -purposes;:

On the" other hand, the use of centrifugal pumps in gasoline dispensingsystems is complicated by thefact thatord-i'nary centrifugal pumps fail to' remairi ina state of prime under all 'con- 1 ditio'nsof- 'operation. Sin-eethe operation of a centrifugal pum-p depends uponthe inertia ofa liquid to-develop the necessary pressure, it cannotpumpif -air enters the impeller causing air Therefore; centrifugal pumps must be provided-Withsome means -for-filling the suction binding.

line and the pump casing with liquid before the pump can discharge. Various-means-have been proposed to-perfdrm-this function. For example, th'e'use'of a'checkxvalve'in the suction line, or

the "use of a smallauxiliarypriming pump, as

Well as'maintaining: theimpeller' under a positive headby locating-aidischarge tank thereabove,',have'al1 been-proposedi- However, sucharrangements have not "proved to -be completely successful" or" practical under all conditions. Clearly; they" have; not" rendered centrifugal pumps suitable'for use ingasoline dispensing systerns Whereina highly volatile liquid must be handled by the pump, It 'lhasalso been proposed to combine: certain features of the rotary posi tive displacement type pump withzfeatures of the'centrifugal type'pumpy'but such devices have.

not been demonstrated to be, a practical solu tion .to. the problem.

One ofthem'ostimportant objects ofmy ine vention' therefore; is to provide aself-priming centrifugalpump of. suchpdesign as to render it practical fo'r'use'iri' agasoline dispensing system, thereby 'elirninating the necessity for employingthe by-pass nonstructionused with rotary positive displacement pum-ps and-permitting the: enjoyment of other advantages'which attenclcthe use of centrifugal pumps:--

Another object of my invention is to provide a centrifugal pump having improved priming means incorporated therewith to eliminate the priming problem which in the past has restricted the broad application of centrifugal pumps.

A further object of my invention is to provide an improved centrifugal pump impeller designed to facilitate priming of the pump.

A still further object of my invention is to consolidate the necessary elements of a pump system with an improved centrifugal pump in a novel manner to achieve an integrated pumping unit having improved design and operational features, and occupying a minimum amount of space.

Another object of my invention is to provide an integrated pump unit of the character described wherein the component parts thereof are all readily accessible without disconnecting the unit from the dispensing system and wherein possible trouble can be quickly detected and isolated to the defective part, thereby reducing the time of shutdowns for servicing thev pump.

A further object is to provide a pumpunit of the character described wherein the individual parts thereof are simple and economical to manufacture, assemble, and maintain.

Another object is to provide in the outlet from the pump unit an improved outlet check valve designed to resist the shock of'suddenpressures developed between the check valve-and meter when the gasoline discharge valve is suddenly closed, thereby preventing damage to the meter and other portions of the dispensing system. v

Still another object is to provide for. adequate drainage and venting from the impeller drive shaft to prevent the hazard accompanied. by the possible leakage of inflammable liquid and vapors along the drive shaft. I

These and other objects/are accomplished by my invention wherein I provide a pump unit" containing withinone compact housing an inlet conduit having a strainer and check valve therein, a centrifugal pump impeller, a. discharge chamber thereabout, a primaryair separation chamber, a liquid discharge conduit from the primary air separation chamber and an outlet check valve in the liquid discharge conduit, and

a secondary air separation chamber having a float operated valve therein controlling a return conduit to the pump inlet'conduit. The float valve aforesaid is the subject of my copending application, Serial No. 290,016. 'To facilitate priming the pump, the impeller, which is characterized by a central inlet eye and a plurality of passages radiating from the central inlet eye to the outer periphery of the impeller, is further provided with lateral passages connecting'w'ith the radiating passages; and a recirculating'or" priming passage is provided between the impeller chamber and theprimary air separation chamber to permit the flow of primingliquid to the lateral passages in the impeller. 'This flow is so controlled that priming liquid is introduced to the radiating passages in the form 'of successive slugs of liquid which serve to entrap successive volumes of air therebetween and drive the air to the outer periphery ,of the impeller, thereby creating suction at the impeller inlet.

My invention may be'best understood by reference to the accompanying drawings and the descriptive matter relating theretofwherein' a preferred embodiment of mypump unit is specifically shown and described;

Referring to the drawings, I

4 Fig. 1 is an isometric view of my pump unit showing the motor connected thereto;

Fig. 2 is a plan view of the pump unit and motor shown in Fig. 1;

Fig. 3 is a section in elevation taken along line 3-3 of Fig. 2;

Fig. 4 is a section in elevation taken along line 4-4 of Fig. 2;

Fig. 5 is a sectional view, looking down, taken along line 5-5 of Fig. 3;

Fig. 6 is a section in elevation taken along line 66 of Fig. 5;

' Fig. 'l is a schematic representation showing the principal elements incorporated in my pump unit;

Fig. 8 is a section in elevation showing the detail of the float valve and mechanism associated therewith which also appears in Fig. 6;

Fig. 9 is a section in elevation showing the detail of the outlet check valve which also appears in Fig. 6;

Fig. 10 is a side view in elevation of the impeller which is shown in section in Figs. 4 and 5;

Fig. 11 isa side view in elevation of the wear ing ring which is shown insection in Figs. 4 and 5; and

Fig. 12 is an isometric view of my pump unit, partly in section, showing the spatial relationship of the elements, chambers and conduits therein.

The general arrangement of elements which I have consolidated in my pump unit may be ascertained from the diagrammatic representationsshown in Fig. 7. A more specific description of my invention, with reference to the'other figures, follows. i

Suction inlet conduit Referring to Figs. 1, 2, 3 and 12, the pump unit housing is indicated generally at I, and the motor and motor bell housing which is bolted thereto is indicated generally at 2 and may be provided with conventional voltage regulator and electrical conduit v connection box as shown. The base of the 'pump housing is provided with a suction inlet 3 which leads into

portions

4, 5

and 6 of a suction conduit delivering liquid to the impeller eye and formed by. partitions. within the housing. The base of housing I is provided with a removable closure 1 which is adapted to position a strainer 8 within portion 5 of the suc-' extends downwardly to form an inlet connection with the impeller l l;

Impeller and impeller chamber The impeller ll, shown in Figs. 4, 5, 10 and 12 is a disc-like cylindrical member which is provided with a collar [2 adapted to receive a drive shaft. An annular inlet passage I 3 surrounding this collar extends into the impeller from one end face thereof and a plurality of radial passages [4 are provided to connect inlet eye l3 with the outer periphery'of the impeller.

The outer periphery of inlet I3 is provided with a, bearing [5 extending outwardly from the end assassin face of the: impeller. which carries beaminga I Lateral passages I-B, the-purpose of w hiehiwilk hereinafter appmr are; provided; atepointsz adjacent the bearing. to connecttradial ipa'ssages l il-- with. the end. face 1 of the impellervcarrying said". bearing. Theimpeller llwsituated within an: impeller: chamber I1 formed between i aaparti-tion x lflnw-ithin.the-housingI and the endplate I9Vof the bellhousing for motor12 Bearing; I5? of. the impeller operates Y against portion of? par-- tition l8 andaiwearingring 20-, rig-idly secured to partition I 8 by means.v of bolts-2 I counters" sunk within thewearinggring in.-.counterbores .22. The wearingring 20(is@funtheriprovidedsas" shown a iniFigs. 5, 11. and 12.,.with. arcuatei passages 23: which communicate. impeller chamber; I! withthe region or, lateral. passages Y I 6-in impeller. l-I Partition 4 I 8 istprovided .withiairecirculationipassage to communicate a-sourceoi primingfliqui'd; with impeller chamber. H. and thence throughpassages 23 in Wearing; ring, 21) toipassagest I6 in the. impeller. 7

As. stated. hereinabove the impellers i I is; so constructed that. priming: liquid is: introduced .to the radial passages I in the: formwof-l successive slugs. of. liquidv from. the-primary.- air. separation chamber. to entrap air from. the. suctioniinlet 6- and. prime the pump, To. accomplish this: result, the-size and numbenoi-the radial passages Iliandlateral passages: I6, .as.well:as the size and numberv 0f.arcuate passages 23 .mayi vary-de pending .upon anumber of considerations- The:

pump capacity -wil1 depend,. within certain :limits; primarilyupon the size-and. number of .the radial.

passages-M and the speedlof impeller rotation; although other factorsobviously, influence pumpcapacity For, any. particular impeller capacity wherein the sizeand number. ofiradial passages I4 have beenchosen, having theeimpeller speed in mind, the sizeandinumberoi both .the arcuate. passages 231 in wearing, .ring 2 0 andthe lateral. passages. i (lin the impeller should'besuch .that before a. slug of liquid is, discharged 7 from"; any radialv passage .du-ring priming, another slug; of.- liquid is introducedsothatla. liquid seal-list at possible volumes of; air. orv vapor. between suecessive slugs. The frequency, of these-slugs, inturn, is determinedflb'y thespeediof impeller II and the number ofpassages .directlyconveying.

priming liquidto the region of lateral passages I ii. For the embodiment specifically shown herein, two such passages 23 in wearing ring 2B are provided for this purposes However, one or more may beemployeddepending,upon the iactorsdiscussed. It is preferred touprovide.sucn passagesr as 23 in pairs to balance-the forcesiacting ;uponimpeller. I I during, priming.. Moreover; although passages '23 are shown disposed in the horizontal plane, the vertical plane or any-othersplanemayw be suitable as-long'as primingi'liquid'is always-'1 in. communication therewithz'e.

' 4 all times maintained between the inlet and out It shouldzbeznoted in conneetiomwith impeller:'

I I that.

pa sages'sl

4 ,1 althougtlffshown 'to be radial;v

6:. may-,- radiate from-ithe inleteyew I3 ito theeouter periphery, in other respects than that specifically shown-s PassagesaI I-rm-ayintersecteye. It tan gentially'and/or: may be: curved...

Impeller I I is keyed to a shaft 2 5which is driven bylmotor 2 and which is'journaled in bearing a. Key.- gfi and .locknut 21 areiprovidedfor this purpose. Apacking ring-ZS'issituated between impellerwlI andplate hand-is rigidly secured to plate I 9 by--means 0fcountersunk screws-or" rivets 28w. within packingring-lii in counterboressame. provide. as working surface for apacking; A packing and. packing gland. resiliently urged against packing--ring:28"by-aspring, all of which are -generally indicated rat'29, are provided withinend-,platel B te; minimize fluid leakage along shaft 2 5.. As. an addsed precautionarymeasure should there occu-rleakagearound packing 2il andialongshaft 25, conduits; asshown, are provided .fromthe/motorv side of the packing andterminating with. ported vent plugs -39 i and t! --to exhaustsuch leakage-from the pump unit:-

ImpeZZ'er discharge chamber An impeller discharge chamber- 32 shown .in Figs. 3, 4, 5 and 12, is provided within housing I and extends about the outer periphery of impeller Il and communicates therewith. This impelleridischarge chamber; may-stake any con- :venient form-such as that' ofa doughnut; but'is- I may a be "provided inconjunction iwith outlet andextending-wi-thin impeller discharge'chambcr 32 to facilitate-directionof.theliquid in the im'-- peller idischargechamhen toward: the outlet F 33 I Primary .azf separation chamber The-:primaryiair separation chamber 34, shown in" Eigs ;3-,= 4;: 5, and i 12, .isa= relatively large chamber compared to other portions of the pump unit"and.'iS separated from impeller chamberli byipartition; I 8 and bounded by". the suction inlet conduit i 6 leadingfto' the. impeller eye I3. The pmrposexof 1 the primary air separation" chamber, asithewname implies." isto separate the'air and" diifficul tly condensable' vapor from the liquid which has been ifreshlygpuinped and discharged thereinto; Tli-isrma-y-bedueto' aeration or cavitation caused-by: the "centrifugal pump or simply due 'to the presence-'ofiair crvapor on the' inlet side ofthe pump; The immediate discharge from-outlet 33 or impeller discharge chamber 32 passesinto a' well ee form'ed"byla'baiiie 35-wit'h-. in primary airiseparation chambert l to prevent saturation of an ith'e' liquid within chamber 3 3 with-sail? Th'iS -WBH zdirects the saturated liquid to rthe top etchamber 3a, where it releases the air: and/or vapor;- leaving the'liquid outsidao f w.el1' 3 l-free-of airand'entrained vapor: Thus, the "liquid available for priming through passage M randa for discharge from the pump: unit through conduit 38, described hereinafter, is maintained. air. andvapor-free. The level of liquid in chamber 34 will remain near the top of the charnbez"at all times unless there is a leak in the system. At the lowest level liquid couldf all' irr *chamb er- 34} there would still remainsuili cient liquid to reprime the pump. Furthermore, a liquid seal is normally maintained over the outlet 33 of impeller discharge chamber 32 which helps prevent the impeller chamber from accumulating air when the pump 'is idle and facilitates priming. During repriming and normal operations the air and/or vapor separating from the liquid as it reaches the top of chamber 34 is forced into a restricted conduit 31. Conduit 31 may be an ordinary tubing containing an orifice therein. Recirculation passage 24 in partition |8 is preferably disposed below the central portion of the impeller to: insure at all times an adequate so-urceof priming liquid from the pri-' mary air separation chamber 34 to the impeller II. A pump outlet conduit 38 extends downwardly into chamber 34 on the opposite side of baffle 36 from well 35 to receive air-free liquid from a point near the bottom of primary air separation chamber 34. This outlet conduit con tains a check valve generally indicated at 39 disposed therein and extends laterally beneath the top of housing terminating in outlet passage 40, to permit the placement of a removable closure 3| above valve 39 for installationand removal of the valve.

Outlet check valve Outlet check valve 39, shown assembled in Fig. 6 and shown in detail in Fig. 9, is designed to resist the shock in the fluid column above the check valve when the outlet valve in the gasoline dispensing hose is closed following a dispensing operation. In many dispensing systems, when this dispensing valve is closed, the inertia of liquid in the system frequently tends to build up pressures on the outlet side of the check valve between pump and meter which tend to snap the valve upon its seat with such force that serious damage is apt to occur. Accordingly, valve 39 is so constructed and designed that it will resist initially'any impact exerted thereupon as a result of sudden pressures developed thereabove. Basically, the valve consists of a valve seat 42 which is adapted for insertion within outlet conduit 38, a valve disc 43 cooperable therewith, preferably of a shock absorbent material such as cork, a valve stem 44 riding within a valve stem guide 45, a. collar 46 on said valve stem and above valve disc 43, and a spring 41 operating against collar 46 for urging the valve disc toward the valve seat. Beneath valve disc 43, valve stem 44 is provided witha piston 48 reciprocable within the hollow cylindrical member forming valve seat 42 and having a. loose fit therein, and the lower portion of piston 48 is provided with a. taper. The effect of this construction is that any sudden downward motion of the valve toward its seat will tend to become retarded before disc 43 contacts seat 42, due to the action of piston 48 exerting pressure upon the liquid beneath. However, the slight clearance pro vided between piston 48 and the cylinder within which it operates permits leakage of liquid therebetween and ultimate closure of the valve as long as a sustained pressure above the valve exists, overbalancing the pressure therebeneath. Thus, the valve 39 is permitted to close when desired, but unnecessary shock during the closing operation is eliminated.

Secondary air separation chamber The air which is permitted to bleed from primary air separation chamber 34 through restricted conduit 3'| will invariably contain volatile 8. vapors and may also-contain entrained liquid. To recover as much-liquid as possible passing through conduit 31 and to facilitate further air separation, a secondary air separation chamber 49, shown in Figs. 5, 6 and- 12, is provided within the pump unit. This air separation chamber is provided with an air vent 50 in the top thereof, shown in Figs. 1 and 2, a float 5| of any suitable buoyant material such' as cork, and a float operated valve to control the liquid level therein. Float 5| is disposed upon a vertical rod 52 connecting at the base thereof with the needle portion 53 of a needle valve having a seat 54 situated in the'base of chamber 49 and disposed about needle 53 in the form of a collar, as shown in detail in Fig; 8. This'needle valve is in communication with a conduit 55 extending therefrom in the base of housing to portion 4 of the suction inlet conduit to the pump unit. Thus, as the float 5| rises within the secondary air separation chamber in response to the liquid level therein, the needle valve is opened and liquid recirculates to the suction inlet. The portion of chamber 49 abovethe liquid level therein is under atmospheric pressure due to air vent 50 provided in the top thereof communicating with the atmosphere, as shown in Figs. 1 and 2. For this reason and for the reason that the conduit 55 is under suction, the needle valve may tend to stick to its seat, although the liquid level within chamber 49 has risen to a point which should cause the float 5| to open the valve. To insure that this condition will not occur, the pressure of fluid coming from conduit 3'! is employed to assist opening of the valve, as shown in Figs. 6 and 8. For this purpose, the top of chamber 49 is provided with a removable closure 56 to which conduit 3'! is connected. 'A cylinder 51 having a central bore 58 therein depends from removable closure 56, and rod 52, upon whichfloat 5| is mounted, extends upwardly within bore 58 to form a small piston 59 operating within bore 58. The top of bore 58 is provided with a lateral passage 60 extending therefrom to the chamber 49 to permit elevation of piston 59 within bore 58 when a pressure is developed therebeneath. To develop this pressure, another passage 6| is provided within cylinder 51, extending from a, point in communication with conduit 31 and directing at 62 a jet against the lower face of piston 59. Rod 52 is tapered at 63 immediately beneath piston 59 and passage 64 communicating with this portion of rod 52 is provided to permit fluid from conduit 31 and passages BI and 62 to pass into chamber 49 except when piston 59 is fully elevated. When piston 59 is fully elevated, the tapered portion of rod 52 enters bore 58 to prevent passage of fluid from primary air separation chamber 34 through passages 6|, 62 and 64 into secondary air separation chamber 49. Thus when secondary chamber 49 accumulates sufficient liquid, fiow of further liquid thereto is avoided until most of the liquid has been exhausted through valve 53.

Operation The operation of my pump is as follows: Assuming that the pump has been initially installed in a dispensing system, it is necessary to fill the wearing ring;2 |lto t-he region of the lateral pas-v seamen sages Itin impel-lord -he rotationof impelleri l with respect-to wearingring 2-0 will cause periodic communication of each lateral :passage 16 with passages '23 in wearing ringflfl. Passages Iii-are so designed that each time this communication occurs a slug of liquidwillbe introduced into the corresponding radial passage M causing a liquid seal therein. Rotation -of-- the impellerand the introduction of successive slugs oili uid-i-n each radialpassagebefore the preceding's-lug' becomes discharged from the impeller periphery causes entrapment of air within the impeller and builds up :suction --at the impeller inlet. The air and liquid thus discharged from the impeller during priming will pass into and through the impell er discharge chamber 32' to the rimary airsepara" tion chamber 34 whereintheair is-permitted-to separate from-the surface-oi the liquid and-the liquid becomes available ;for further priming. This sequence continues, employing the same body of liquid in the primary air separation chamber "for priming-until any air in the pump inlet line or the suction inletconduitbecomes discharged from'the system and-the pumpstarts to pump" liquid from the inlet conduit. Once this occurs, -pressu-re beginsto-build up "within the primary air separation chamber 3i until it attains pumping pressure 'Whereupon liquid is available for a dispensing operation. However, check-valv 39 will'remain closed, due to the pressure in the metering-and discharge system thereabove, until the outletval-ve in the dispensing hose-is opened. This releases the pressure above check valve 39 and-permits thenow liquid therethrough fromthe pump unit. In the meantime, any air which -'--has developed in A the primary air separation chamberand --separated from liquid therein bleeds eff-through conduit 31 into secondary air separation chamber wherein further air separation occurs, the air being exhausted to theatmosphereandthe liquid being returned to suction conduit -4-through conduit 55 when the liquid level -within chamber 49 becomes sufficienttoopen valve-53. -'l?he opening ofvalve 53' is assisted'by the jet action of fluid under pressure at -62 against the face of piston 59, insuring that the valve will notstick to seat-54 when apredetermined quantity of liquid accumulates in chamber =49. When valve 53 opens, the action of -piston -59- and float causes piston-59 to become completely elevated within bore 58-such-that the-taperedportion t3 of ro'd 52 interrupts the flow'of fluid from-primary air separation chamber =34 to-"secondary air separation chamber 49. This provides anopportunity for most --of the liquid to be exhausted from chamber 49,-so that the chamber will-not become flooded were liquid toenterthechainber faster than it could be removed. Such flooding, which is-common in -gasoline dispensing systems employing float controlled air-separation chambers, could be serious if liquid were permitted to escape from vent 50. When chamber 49 becomes sufficiently exhaustedof liquid, the weightof the float valve assembly will'carry valve 53 back to its seat despite the pressure acting upon piston 59. In=addition, piston-59 performs the-further function ofhastening the attainment of [pumping pressure within chamber 34. Between-operations, when-the pump. is. not working, chambent l is. under atmospheridpressure. .Whenthe pump, startsragain, chamber :34 must rapidly rebuild: its lost :.pressure .to :sufficient: magnitude for .a dishursing operation. In starting, some; liquid from chamber. initially in .thetform of a liquid ietis forced into chamber lQ-under normaLoperating conditions, such that float 5l and piston tithecome elevated, thus interrupting communication between chambers :34 and49. since pressure relief-irom chamber 3 1 isthereby cut off, thispermits-thepressure within chamber 34 to build up more rapidly than were pressure relief afforded for chamber 34'throughsecondary chamber 49.

Once the pumpisin a primed condition, inlet check valve- 9 will ordinarily holda sufficient column of liquid-in the'inletconduit so that little recirculation throughpriming passage 24 i is .necessary. For this-reasom-passage 24 maybe provided-with asmall check valve, not shown, de-'- signed to interrup t liquid flow therethroughto the impeller I l when the pump is in :aprimed conditionand the liquid inthe primary air separation chamber 34 is under pressure. However, during summer operation Whengasoline tends to volatilize, andaiterlong periods of. idleness, an air or vapor lock mayiorminthe suction inlet conduit. This-presents-no-,problem-to the operation of=my pumpsince the primingfacilitiesof the primaryair separation chamber through passage 2-4 :are :iully capable of .meeting this contigency, as they are after initial installation of my pump unit in a dispensing system.

The attainment-of the objects of my invention previously set forth should-make apparent many of the advantages or my inventionand thevarious applications thereof. aP-erha-ps mostsignificant of these advantages is the-fact that I have provided a practical pump unit for employing a centrifugal pump in a gasoline dispensing system and ans-improved priming :means therefor. In thisconnectio-n Lhave-providedan improved impeller-construction of wide flexibilitywhich enhances the applicability of my pump unit i in gasoline dispensing systems. With present-dispensing rsystems, when it is desired to substantiallyincreasethecapacity of the system, it-is necessaryto employa larger pump. However, with mypumpunit this result .may be accomplished simply by-performinganexchange of impellers, employing an impeller 'having a larger number of rad-ial passages or radial passages of greater :size. Thus, v thesame pump unit may be variously used for 'dispensingsgasoline to automobiles or trucks simply by choos-ing the appropriate impeller.

In addition, the construction and arrangement or secondary air-separation chamber ii and its associated elements eliminates the danger of flooding, which isv a frequentmalady characteristic of many dispensing systems, andalsopermits more .rapid attainment of pumping pressure in chamber 34. in short-the float valve and jet assist design in secondary --chamber it lends for better pump operation.

Other important advantages-orally invention accruefrom the novel form of integrated construction Ihave provided. In ordinary gasoline dispensing systems it is customaryto locate afoot valve in the conduit extending down into the storage tank. By-placinga check-valve within my pump unit and a strainerin advance thereof, I have eliminatedthe-needfor a root valve-and in turn have eliminated a frequent source of trouble which attends-the useof such systems. The strainerwill prevent unseating of the valve dueto, possibleextraneous material in the gasoline. Furthermore, all .valvesand partsin my pump :;unit :are .readily accessible for servicing through. theifour, removable closures 1, WA] and 5 6, and motor-end plate l I 9, without-the necessity ll of disconnecting the entire pump unit from the dispensing system. In addition, my integrated pump unit saves space, which is thus made available for more flexible installation and maintenance of the pump unit and other accessories used in connection therewith. The manufacture, assembly, and maintenance of ordinary dispensing equipment, because of the size of the various parts and connections, is expensive, heavy, bulky, troublesome to handle, and not too efficient. It occupies space in proportionjto the number of these part and therefore requires larger enclosures with heavier structural members. All of this means increased cost. On the other hand, my pump unit has reduced the number of parts to a minimum to provide economies in manufacture, assembly and maintenance of an attractive magnitude.

It should be understood thatmany modifications may be made of the specific embodiment I have shown and described herein and equivalents of many elements I have employed in combination may be used without departing from the spirit of the invention. My invention is to be limited solely by the scope of the claims hereinafter made.

I claim:

1. In a centrifugal pump having an inlet, an outlet and an air separation chamber communicating with said outlet, the improvement therewith for priming comprisinga relatively fiat cylindrical impeller provided with a central inlet eye, radial passages in said impeller connecting said eye with the outer periphery thereof, lateral passages in said impeller located adjacent said eye, each said lateral passage extending from an end face of said impeller to one of said radial passages, an annular chamber communicating directly with a face of, said impeller and communicating with the liquid in'said air separation chamber through a passage therebetween, a wearing ring in said annular chamber cooperating with said impeller face and provided with a duct directing liquid from said annular chamber to th region of said lateral passages in said impeller.

2. In a centrifugal pump having an inlet, an outlet and an air separation chamber connecting with said outlet, the improvement therewith for priming comprisinga relativelysflat cylindrical impeller provided with a central aperture adapted to receive a drive shaft and an annular inlet passage thereabout extending through an endface of said impeller, a bearing around the outer pee riphery of said annular inlet passage, said cylindrical body being further provided with radial passages of circular cross section connecting said annular inlet passage with the outer periphery of said impeller, and lateral passages located at points adjacent said bearing and spaced a substantially equiradial distance therefrom, extending to said radial passages from the end face of said impeller carrying said bearing, and means adapted to periodically communicate each lateral passage in said impeller with liquid in the air separation chamber as said impeller rotates. r

3. In a centrifugal pump having an inlet, an outlet and an air separation chamber connecting with said outlet, the improvement therewith for,

priming comprising a relatively fiat cylindrical impeller provided with a central aperture adapted to receive a drive shaft and an annular inlet passage thereabout extending through an end face of said impeller, a bearingaround the outer periphery of said annular inlet passage, said cylindrical body being further provided with radial passages of circular cross section connecting said annular inlet passage with the outer periphery of said impeller, and lateral passages located at points adjacent said bearing and spaced a substantially equiradial distance therefrom, extending to said radial passages from the end face of said impeller carrying said bearing, and an annular chamber communicating directly with a face of said impeller and communicatin with the liquid in said air separation chamber through a. passage therebetween, a wearing ring in said annular chamber cooperating with said impeller face and provided with a duct directing liquid from said annular chamber to the region of said lateral passages in said impeller.

4. An integral casting for a centrifugal pump comprising a housing provided on a side thereof with a recess forming an impeller chamber adapted to receive an impeller and a motor mounting plate, an inlet in the base of said housing and an inlet conduit extending laterally to the side thereof and vertically to the top thereof and downwardly to form a suction elbow delivering centrally into said impeller chamber, the top and bottom portions of said housing at the ends of the vertical portion of said inlet conduit being formed with openings adapted to receive removable closures and said inlet conduit being adapted to receive a strainer and a check valve thereabove, a volute surrounding and communicating with said impeller chamber and discharging downwardly and laterally therefrom, an air separation chamber extending beneath said suction elbow from the discharge portion of said volute, the partition separating said air separation chamber from said impeller chamber being provided with a connecting passage, a baffle within said air separation chamber forming a well about said volute discharge, said air separation chamber having an opening in its top to receive a removable closure and a second, smaller opening in the top thereof adapted to receive a restricted conduit for air discharge, an outlet conduit beneath said removable closure and adapted to receive a check valve and extending laterally therefrom to form an outlet from said housing, a float chamber adjacent said air separation chamber and inlet conduit adapted to receive a float and a. float operated valve in the base thereof, said base being provided with a conduit connecting with said pump inlet conduit, and the top of said float chamber being provided with an air vent and further having an opening for reception of a removable closure carrying the restricted conduit from said air separation chamber.

5. A centrifugal pump comprising a housing provided with a recess forming an impeller chamber, an impeller mounted therein, an inlet in the base of said housing and an inlet conduit extending laterally to the side thereof, thence vertically and downwardly to form a suction elbow delivering centrally into said impeller chamber, the top and bottom portions of said housing at the ends of the vertical portion of said inlet conduit being formed with openings adapted to receive removableclosures and said inlet conduit being adapted to receive a strainer and an inlet check valve thereabove, a volute surrounding said impeller and discharging into an adja-,

closure and a second, smaller opening adapted to. receive a restricted conduit for air discharge, an,

outlet conduit beneath said last-named remov- References Cited in the file of this patent UNITED STATES PATENTS Name Date Russell et a1 Apr. 20, 1926 Number Number 5 Number Name Date Morgan May 27, 1930 Dean et a1 June 13, 1939 Sharp et a1 Sept. 17, 1940 Bogdanofi Apr. 29, 1941 La Bour June 3, 1941 Peter June 24, 1941 Jacobsen July 8, 1941 Adams Dec. 29, 1942 Felzer et a1 Oct. 23, 1945 Jones Oct. 12, 1948 Mueller July 26, 1949 FOREIGN PATENTS Country Date Germany Aug. 15, 1929 Germany June 20, 1931