US2827858A - Foam-making pump - Google Patents

Description

J. c. HESSON FOAM-MAKING PUMP March 25, 1958 Filed Jui 9, 1956 4 Sheets-Sheet 1 March 25, 1958 ,1. c. HESSON I 2,82

FOAM-MAKING PUMP Filed July 9, 1956 4 Sheets-Sheet 2 March 25, 1958 J. c. HESSON 2,827,858

FOAM-MAKING PUMP Filed July 9. 195a 4 Sheets-Shet 5 March 25, 1958 J. c. HESSON' FOAM-MAKING PUMP 'Filed July 9; 1956 4 Sheets-Sheet 4 United States Patent G FOAM-MAKING PUMP James C. Hesson, Riverdale, lll., assignor to Cardox Corporation, Chicago, Ill., a corporation of iilinois Application July 9, 1956, Serial No. 596,554

6 Claims. (Cl. 103-=-136) This invention relates to new and useful improvements in pumps and deals more particularly with vane type pumps for delivering large quantities of fluid at relatively low pressures.

The mass application of mechanical foam, formed of water, a foam stabilizer and air, is widely used for the extinguishment of certain types of fires. it is also well known that the production and delivery of such foam can be accomplished with a vane type pump, the intake of which is flooded by the controlled admission thereto of the liquid ingredients of the foam in the desired proportions. The quantity of liquid admitted to the pump is less than the actual displacement of the pump, however, and the balance of the displacement is made up of air which is drawn into the intake of the pump through an open air inlet along with the liquids. The liquids and air are thoroughly churned within the pump and the resulting foam is homogenized while passing through a series of screens in a stabilizing chamber at the outlet of the pump.

Certain operational difiiculties have been encountered in the past in connection with the use of vane type pumps as described above. For example, the inlet and outlet ports of the pump housing must be large it the pump is to operate properly. This means that the vanes moving across the ports will be retained against radial outward movement by a very limited engagement between their outer edges and the inner surface of the housing. The

engaged portions of the vanes and housing at the inlet and outlet ports, therefore, are subjected to excessive and nonuniform wear and the irregularities thus formed in the edges of the vanes will reduce the efficiency of the pump and may result in breakage of the vanes after a relatively short period of use. I

A further problem encountered in the use of vane type pumps results from the accepted practice of having the eccentricity between the vane rotor and the inner surface of the housing so arranged that the vanes are moved to a position of minimum radial extension just as they move past the outlet port. During movement of the vanes from the outlet to the inlet port, therefore, the vanes are moving radially outwardly and the volume of the space formed between each two adjacent vanes is increasing. This creates a vacuum in each such space during a portion of each revolution of the pump rotor and increases the power required to operate the pump.

It will also be appreciated that any increase in the churning action or turbulence created Within the pump adds materially to the effectiveness of the pump as a foam producing device.

It is the primary object of this invention to provide a vane type pump that is so constructed as to minimize wear of the vanes and produce a maximum quantity of foamper unit of power supplied to the pump.

A furtherimportant object .of the invention is to providelsucha pump which will substantially eliminate any pressure differential acting on opposite sides of tl e vanes amass Patented Mar. 25, 1958 v '2 approaching the inlet of the pump so that the pump will operate without unnecessary drag on the rotating parts thereof.

Another important object of the invention is to provide the above mentioned type of pump with relatively large inlet and outlet ports, and to support the vanes during their movements across said ports in such a manner as to prevent nonuniform or excessive wearing of the outer edges of the vanes.

Still another object of the invention is to provide a vane type pump wherein the foam forming material passing through the pump is subjected to the churning action of a relatively high velocity spray before its release at Figure 4 is a fragmentary sectional view taken on line 4-4 of Fig. 3,

Figure 5 is a top plan-view, partly broken away, of the housing illustrated in Fig. 3, and

Figure 6isa single plane projection of the cylindrical inner surface of thepump housing showing thepositions of the inlet and outlet ports of the housing.

In the drawings, wherein for the purpose of illustration is shown the preferred embodiment of the invention,

and first particularly referring to Figs. 1 and 2, it will beseen that the pump housing, 7 is chambered to provide a cylindrically shaped inner surface 8. The housing '7 also is provided with an inlet passage 9, which is arranged tangentially of its bottom portion, and an outlet passage 11, which extends vertically upwardly from the upper portion of the. housing. The inlet passage 9 opens into the chambered interior of the housing 7 through an inlet opening 12 and the outer end of the inlet passage communicates with an inlet manifold 13 which is mounted on the housing 7. In the upper portion of the inlet manifold 13 there is provided an air inlet passage 15 which opens to the atmosphere through a screen 16. Liquid is admitted to the inlet manifold 13 through a hose adapter 17 which is mounted on the opposite side of the manifold fromthe inlet passage9. An open drain port 13 is provided in the bottom of theinlet manifold 13 for communication" with the outer end A of the inlet passage through the horizontally arranged passageway 18a.

The. outlet passage 11 opens into the chambered interior of the housing 7 through an outlet opening 19 and the upper end portion of the passage has mounted therein a plurality of screen discs 29 through which the material discharged from the pump must pass. At its outer end portion, the outlet passage 11 communicates with an outlet coupling 21 which is mounted on the housing '7 for connecting the pump to a discharge pipe, or the like, not shown.

End plates 22 and 23, see Fig. hare mounted on opposite ends of the housing 7 and are provided with eccentrically arranged hub portions 24 and 25, respectively, for receiving the axially aligned, antifriction bearing units 26. These bearing units rotatably support a longitudinally extending shaft 27, one end portion of which extends beyond the end plate 22 and through the cap 28 of which extends beyond the end plate 23 and into a gear casing .29 that is mounted.omthe:housingflou-twardlymf the end plate 23.

Keyed to the shaft 27"hetween the end plates 22 and 23 is a cylindrically shaped rotor 31 having five longitudinally. extending;v radial. webs;.32. arranged at: equally,

spaced points between .andconnectingi the peripheral por tion 33 of the rotor'a'nd the hub 34 thereof. Boththe' peripheral-portion..33 and thehub. 34..have.. theirropppsite ends. positionedj in closely spaced. relationship... with. the opposed innersurfacesof'fthe end..plates..22.. and 23.... Seal assemblies.35.are providedat. oppositeends of the hub 34to.preventthelflow.of.liquid.between the ends of the hub and the associated inner surfacesmf, the. end.

walls -22.and, 23.. If, ...ho.wever, anyrliquidrescapes past the seal j assemblies, 35, this; liquid will. encounter the. slinger rings 3.6..andL37,'mounted.on.the. shaft-27ibetween downwardly through. the channels and;will bereleased through the. ports 39.1

Formed in each..web',32 ofjtherotor. 31 isflalongitudie nally extending, radially: outwardly opening slot 41; the

slots of circumferentiall'y successive: Webs, havingfitted.

therein vanes 42a, 42h, .420, 42dfa'ndl42e. Theseyanes are freely movable in a radial'dii'ection in their. associated slots Aland. it .will be readily. apparent thatr'ota tion of the rotor 31' willcause thecentrifugaltforces.

acting on the vanesto maintaintheouter edges ,oflthe latter in sliding engagement with the inner surface. Set the housing 7.

That end portion of ithe shaft 27 whichext'ends be yond the end plate 23 into the gear casing 29 haskeyed thereto a gear 43' which-is] arrangcd"in meshingrelationship with apinion 44., This, pinion is keyedltoe.

stub shaft 45 which isrotatably mounted" in the. gear casing 29 and one endv portion of which projects outwardly therefrom for driving connection with any. suitable prime mover, not shown; Rotation of the shaft.45;

therefore, will causethe pinion-44'torotate-the gear 43" and its attached shaft .27 to impart rotarymovement to the rotor 31 within the chambered interior of the housing 7.

By reference to Fig. 2, it willbe readily apparent that the eccentric arrangement'of the shaft 27 "relative to .the inner surface 8 ofthe housing 7 is, such that theperipheral surface of the rotor; 311 lies in closely spaced'relationship with the inner surface of. thehousing at the departure'side of'the'. outlet opening 19' in-- accordance withthe direction ofrotation" of the rotorpas indicated by the arrow A. In other words, the space between the peripheral surface of the rotor 31andfthe inner. surface 8 of the housing 7 expands in. the. direction of rotation of the vanes-42a to 42e-from a. minimum-clearance at.

fined by the peripheral surface-oftherotor 31, the inner surface 8 of the housing' 7 andeach adjacent pair of' vanes 42a to 42e increases fromaminimum'value, when.

the chamber is centered'on-thetl" line, to a'maximum value, when thechamber is-centered on the 180 line,

and decreases from themaximunr to' the minimumwalue during the remaining-one half" revolution. Of course,

while a chamber is passing the 0 line, the portion of the chamber on one side of the'lineis increasing in volume and theportion on the other sideof the lineis decreasing in volume, the two portions being separated from" each other by the 0 line of minimum: clearance: be-. tween the rotor 31 and the inner surface 8 of' the housing 7'.

Referring now- 'to -Fi'gsr 3 to 6, inclusive, for: a' detail description-of the-'pump housinga'l; it'*will be noted that* the" inlet'passage 9': and outlet passage 11 areshorterthan, and are centered longitudinally of, the inner surface 8' so that the opposite end portions of the inner surface are circumferentially continuous for uninterrupted engagement with the opposite end portions of the outer edges of the vanes 42:: to 42s to limit radial movement of the vanes in the slots 41. Circumferentially spanning the inlet opening .12 are a pair of vane retaining bars 46 which converge from the circumferen- 1: tially continuous endportions of=the inner surface 8 toward the center of the housingj intherdirection oh, rota.- tion of the vanesv 42a to.42e. V

The bars 46 are symmetrically arranged relativeto the circumferentially extending center'line of the inner sur- 5 face it and the inner surfaces'z47 of:the. bars are'longitudinally aligned with and form a continuation of the inner surface 8 across the inlet opening 12. As is best illustrated in Fig. 4, the sides of the bars 46 facing outwardly from the chambered. interior ofithehousing 71 are taperedto minimize any resistancetothe. flow of. fluids:

into the chambered interior ofthe housing past the bars=,.

Centered longitudinally of the inlet opening= l2 is a;-. vane retaining. tongue 48 which projects circumferentially from the approach side of-the inlet opening. The.

inner surface 49 of the tongue 48 is also alignedw-ith the inner surfaces 47 of the bars 46 -and the innerrsur face 8 ofthe housing. It .will be readily-apparent, therer;

fore, that.the vanesf42a. to 42:2 moving,past. the.,inlet. opening 12 will, becontinuously supported at; the: oppp site. end portions of their outer. edges by. the. inner, sur: face 8-.of the housing and the intermediate portion of.the outeredges. of. the vanes. will be supported first by b0th;r the inner surface. of thetongue. 48 and.tl1e, inner: SllIzw faces 47 ofthe bars 46 and subsequently, by.the..con-.. verging inner surfaces 47 of the bars 46 so that .any wear;

produced by the engagement of the vaneedges with/thew tongue and bars .will be uniformly, distributedalong the. lengths of such edges.

Formed in the inner surface 8 of the housing 7. area pair of vacuum relief grooves .50 .whichare alignedwith, the spaces formed between the,oppositesidesbf. the. tongue 48 and the bars and. extend.- circumferentially. fromthe approach side of the inlet opening 12... Inother, words, the circumferential length of the grooves. 50.T.is.. such that they open radially inwardlyinto. substantially,

.all of the divergingspace. between the.roto r 31,and

inner surface 8 on the'approach. side of thednletopem. ing .12..

Extending circumferentially across. the. outlet opening, 19 are a pair. of vaneretainiug bars .51, whiclnareangu; larly arrangedto convergefrom the approacl1 ,.side.. to. the departure side of this opening. It .Will b'enotedthat. the bars 51 are symmetrically arranged with respect to the circumferentially extending center line of.th'e. in'ner.. surface 8 and that the inner surfaces 52 of thetbarsu are longitudinally aligned with and provide. acontinuation of the inner surface 8 of the housing 7.

Formed in the innersurface 8'of the housingflat the approach side of the, outlet opening19,- are.v two, grooves 53, see Figs. 5 'and'6, which diverge radi'allypand' circumferentially from a point that is spacediapproximately from the inlet opening 12 to the adjacentsideof the outlet opening. It will'be noted in Fig. 6'that the portions of the inner; surfaces 52 offthe outerendsf of the bars 51 extend into. the grooves 53"and that the portion of the inner surface 8. between thertwo, grooves forms a triangular vane supporting area 54.v It will"be. readily apparent that the outer edges of the ,vanes.42 Z1.. to 42e moving acrossthe outlet opening will ,besupported against radial outward movement by the circumferentially. continuous end portions. of the inner surface,8':'and;.dur;

ing their approach to, the opening, by the triangular-area 54 of the inner surface 8.' and by the aligned end'portions of the inner Surfaces; SZof'the-bars 51'; Further, durin their movement across the "outlet opening-19; the vanes- 42a to 42e are supported by the converging inner surfaces :32 or" the bars 51 so that any wear on the outer edges of the vanes, due to their engagement with the bars, will be uniformly distributed across those portions of the vanes extending between the circumferentially continuous end portions of the inner surface 8.

Referring once again to Figs. 1 and 2 for a detail description of the operation of the invention, the pump is operated by a prime mover which rotates the shaft 45 and the pinion 44 mounted thereon. This rotation of the pinion 44 will effect rotation of the gear 43 and its connected shaft 27 to cause the rotor 31 and the vanes 42a to 422 carried thereby to be rotated within the eccentrically related chamber in the housing 7. Rotation of the rotor 31 will cause the outer edges of the vanes 42a to 42e to be urged into sliding frictional engagement with the inner surface 8 of the housing 7 by the centrifugal forces acting thereon. When the pump is operating, a properly proportioned mixture of water and a foam stabilizing agent is admitted through the adapter 17 to the inlet manifold 13 to flood the inlet passage 9. The quantity of liquid introduced through the inlet manifold 13, however, is less than the displacement of the pump so that a certain amount of air is drawn into the inlet manifold through the screen 16 and the air inlet passage for mixture with the liquids entering the inlet passage 9 of the pump.

each chamber. Both of these portions of a revolution are related to the position of the leading vane of a pair.

in other words, fluid is being admitted to the chamber behind a given one of the vanes 42a to 42e during movement of the that vane through that portion of a revolution labeled Intake in Fig. 6 and is beingforced from the chamber during movement of the vane through that portion of the revolution labeled Exhaust. It will be noted that the Intake and Exhaust portions of each revolution overlap while a chamber moves past the 0 line so that fluid is being drawn into the portion of the chamber on one side of such line at the same time that fluid is being forced out of the chamberjon the other side of the line. It will also be noted that a slight amount of clearance is provided between the Intake and Exhaust portions of a revolution as the chamber passes from communication with the inlet opening 12 into communication with the grooves 53 so that fluid cannot pass directly from the grooves to the inlet opening.

Considering now the movement of a given one of the vanes42a to 422 along the surface 8 from left to right, as viewed in Fig. 6, and recalling that the space between the rotor 31 and inner surface 8 expands from the 0 line to the 180 line, it will be readily apparent that as a vane moves into radial alignment with the grooves 50 fluid will be drawn from the inlet opening 12 through the By reference to Fig. 2, it will be readily apparent that Y the chamber defined by the peripheral surface of the rotor 31, the inner surface 3 of the housing 7 and each adjacent pair of vanes 42a to 422 increases in volume as the leading vane passes the position of minimum clearance be tween the rotor and the inner surface and continues to increase until the center of the chamber reaches a point diametrically opposite the position, of minimum clearance. The chamber will thereafter decrease in volume until the trailing vane of the chamber has moved across the outlet opening 19. The mixture of air, water and foam stabilizing agent, therefore, is drawn into the above these two vanes will continue to increase in volume so.

described chamber by its increase in volume and is forced from the chamber into the outlet passage 11 by the subsequent decrease in its volume. ,Of course, the mixture of air, water and foam stabilizing agent is subjected to a great deal of turbulence during its movement through the pump and the foam produced by this turbulence is homogenized and stabilized as it flows through the outlet passage 11 and the screen discs 20 into the outlet coupling 21.

Referring now to Fig. 6 for a detail description of the manner in which the outer edges of the vanes 42a to 42e cooperate with the inner surface 8 of the housing 7 during operation of the pump, it will first be noted that the position of minimum clearance indicated by the 0 line of Fig. 2 is also indicated by the 0 line of the projected inner surface 8 illustrated in Fig. 6. Further, the projected inner surface 8 extends from the 0 line in the direction of rotation of the vanes 42a to 42e, as indicated by the arrow A, and the line of contact between'the outer edge of each vane and the inner surface 8, when the vanes are positioned as illustrated in Fig. 2, is shown by broken lines in Fig. 6 and identified by the reference characters of the vanes. Due to the eccentric relationship between the axis of the rotor 31 and the axis of the cylindrical inner surface 8, the spacing between adjacent lines of engagement of the outer edges of the vanes 42a to 42e and the inner surface 8 varies as the vanes are rotated, the minimum spacing occurring when the vanes are at equal distances on opposite sides of the 0 line and the maximum spacing occurring when the vanes are spaced at equal distances on opposite sides of the 180 line.

Fig. 6 also illustrates the portions of each revolution of the vanes 42a to 42e during which fluid is taken into each chamber and during which fluid is exhausted from of a vacuum behind the vanes 42a to 42e as they appreach the inlet opening 12 and will thereby eliminate any pressure differential on opposite sides of the vanes which would tend to resist rotation of the rotor 31.

As the selected one of the vanes 42a to 42e continues its movement along the grooves 50, the next successive vane will move past the 0 line and the chamber between that additional fluid will be drawn into the chamber while the leading vane moves across the inlet opening 12. During the movement of each vane across the inlet opening 12, it will be supported against radial move ment by engagement with the uninterrupted end portions of the inner surface 8 and by engagement first with the inner surface 49 of the tongue 48 and subsequently with the angularly converging inner surfaces 47 of the bars 46. The total area of engagement between the vanes and these supporting surfaces, therefore, is sufficient to prevent undue wear on the vanes and that wear which does occur along the outer edges of the vanes will be uniformly distributed to prevent the formation of any irregularities which might permit leakage of fluids past the vanes.

The trailing one of a selected pair of vanes 42a to 422 will move past the inlet opening 12 just prior to movement of the leading vane of such pair into alignment with the grooves 53 which communicate with the outlet opening 19. When the leading vane moves into alignment with the grooves 53, therefore, no fluid will be permitted to flow from the outlet opening 19 to the inlet opening 12 and the converging relationship between the rotor 31 and the inner surface 8 will cause the fluid to be expelled through the grooves 53 and subsequently through the outlet opening 19 into the outlet passage 11. This expulsion of fluid will continue until the trailing vane of the selected pair has moved past the outlet opening 19.

During movement of the vanes 42a to 42e across the outlet opening 19 they are supported by engagement between their outer edge portions and the uninterrupted end portions of the inner surface 8 and by engagement with the converging inner surfaces 52 of the bars 51 so that the vanes will be subjected to a minimum amount of wear and the wear which does occur will be uniformly distributed across the width of the vane as was previously described in connection with the inlet opening 12.

Since the pressure of the fluid in the outlet passage 11 will, be somewhat above that of the fluid in the inlet passage'9; the movement' of "a chamber into communica= tion: withthe" grooves 153 may permit limited amounts of fliiidto'spray into the chamber. This spray of fluid;

however; willifacilitate'the' formation of foam within the g I parrot-wanes before the vanes are rotated to position such clfamber'and' will increasetheeffectiveness of the pump asa' foam producingdevice:

.Whenth'epump is to be stopped,- the fiow of fluidto theiffletrnanifold 13' through'the adapter 17 is stoppedand" the prime mover for rotating the pump is also stopped; Fluid=entrapped within-the outlet passage 11,- thechambers and the inlet manifold 13 will gradually seep-into thelower portion of the pumpforfiow through the passageway 18a and thedraiu port It is to be understood that the form" of the invention 15 herewithshown and described is to be-taken as apreferred example ofgthe same and-that various changes in the sh-ape, size and arrangement ofparts'may'be resorted to-twithout departing"from the spiritof the invention 01" 20 mounted in said housing for rotation about an axis in spaced parallel relationship; with the axis of said, inner surface; a p1uralityof-l'vanes carried by said 3 rotor for rotation therewith and for-'radialinovement"relative there to to maintain the outer edges-of the'vanesin' slidingrena gagement with saidirinevsurface; and a'plurality ofvane" retaining bars spanning-*eachcf said passages'in'a circumferential Tdir'ection; each -of-said bars having its inner surface aligned with'the inner surface 'of said'housing and: extending: in angular relationship to the direction of movement of it the outer edges of saidvanes across the passage, the inner surface ofsaid housing having grooves" formed-therein to extend chcumferentially fromthe ap proach sides of theinlet and outlet passages, thev spaces defined b'y said rotor, the inner surface of thehousing; and adjacent pairs of vanes communicating with" said passages'throughsaid grooves while the spaces are ap proaching-a position of alignment 'With the passages.

21' Apump, comprising-a chambered housing having'a cylindricallyshaped inner surface andinlet and outlet passages; opening into' -thechamber' of' the housing, a L cylindrical rotor'mounted in said 'housingforrotation" about an axis that iseccentrically located'relative to'the axis' -of said-'inner-surface, the eccentric'relationship be= tweensaid v inner surface and said rotor" causing the opposed faces;- thereof'tof converge in the direction. of rotationof'the rotor'from'ithe" opening of the inlet passage to'the opening ,of the outlet passage'and to diverge fromth'e opening of the'outlet passage to the opening of the inlet passage-,iand aplurality ofvanes carried by said rotor-for rotation therewith and for radial movement. relative thereto to maintain the outer edges oftheivanes in sliding engagement with'the inner surface of the housing, said inner surface of the housing having a groove therein extendi'ngfrom the opening of the inletpassage in a direc.-.

before .the.vanes are rotated toposition-such space in alignment with the inlet opening, said inner surfacezof 8 said housing also having a groove therein extending from the-opening of said outlet passage in-a' direction opposite the directio1rof rotation-of said rotor to provide communication'betvveen such*opeuing-and the contracting space defined by said rotor; the innensurface and an adjacent space in alignment with-the outlet opening.

3' A-pump as defined 'in' claim 2-- further characterized by aipair of=bars spanning each-of said passages in a circumferential-direction,-each-pair of bars havingthe inner surfaces thereof aligned with the inner surface of said housing and symmetrically arranged in angular relationship relative to the I circumferentially extending center line of their associatedpassage;

4. A-pump, comprisinga chambered housing having a cylindricallyshaped'innersuIface and inlet and outlet passages opening into the=chamber of the housing, and a vaned rotormountedeinsaid housing for rotation about an axis in spaced parallel relationship with the axis of said I inner surface; said inner surfacehaving grooves formed therein to extend circurnferentially' from the approach through said grooves while the spaces are'approaching a position of alignmentwith the passages.

5. A-pump; comprising a housing-having a first portion chambered to form a cylindrical inner surface-provided 'withan inlet'opening and an'outlet opening, said cylindrical surface being positionedwith its'longitudinal axis horizontal and' -vvith said inlet opening in communication with its lowest 'point; a vaned rotor mounted eccentrically within said cylindrical surface,a second portion of said housingformed to provide-an inlet passage communicatingwith said inlet opening, the bottom of said inlet passage beinghorizontal and tangential to said lowest point ofsaid cylindrical surface, and an inlet manifold sealingly connected tosaid housing in open communication with said inlet passage, the side of said inlet manifold opposite said inlet passage being formed with a liquid supply opening in=substantial alignment Withsaid inletpassage so asto form a substantially straight flow path-between said liquid supply openinga'nd saidinlet opening, and the bot-- References'Cited in the fileof this patent UNITED STATES PATENTS 1,737,942. Bagel. Dec. 3, 1929 2,216,053" Staley Sept.. 24, 1940 2,335,284 Kendrick" Nov. 30, 1943 2,569,185 Mc'Kibben et a1 Sept. 25, 1951 2,717,770 Gibsoriet al Sept. 13,195 2,781,000 Thomasret a1! Feb. 12,1957

,FOR'EIGN PATENTS 425,258" Italy. Sept. 18,1947 686,452 Germany Jan: 10, 1940

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