US3179382A

US3179382A - Blending pump

Info

Publication number: US3179382A
Application number: US262057A
Authority: US
Inventors: Omar S Knedlik
Original assignee: Individual
Current assignee: Individual
Priority date: 1963-03-01
Filing date: 1963-03-01
Publication date: 1965-04-20
Anticipated expiration: 1982-04-20

Description

A ril 20, 1965 O. s. KNEDLIK 3,179,382

BLENDING PUMP Filed March 1, 1963 2 Sheets-Sheet 1 IN VENTOR. 0m? zi'flz'flzm 4 rfaE/VEYS United States Patent This invention relates to fluid metering and mixing pumps and more particularly to an improved blending pump.

The term blending pump as used herein refers to a variety of pump especially used to mix a plurality of fluids together in predetermined quantities and simultaneously pump the mixture so produced to storage containers or mixture processing equipment. As an illustrative example, pumps of this variety are useful in the production of ice cream to blend the desired quantity of air with a liquid ice cream mix and delivers the foamed mixture directly into an ice cream freezing machine.

It is an object of the present invention to provide an inexpensive pump for accurately blending a plurality of fluids together in predetermined proportions and delivering the mixture thus formed to a point outside the pump.

It is another object of this invention to provide a blending pump composed of a plurality of interchangeable modules which can be associated in a desired numbet and a desired capacity to effect the blending of predetermined proportions of a desired number of fluids.

It is a further object of the present invention to provide a blending pump comprising a plurality of modular stages in which a fluid is added radially of a first stage, metered thereby and pumped axially into an adjacent stage having a larger volumetric capacity and wherein a second fluid is added radially of the second stage, combined with the first fluid, and pumped from the second stage axially thereof.

Yet another object of the invention is the provision of a blending pump comprising a plurality of individually housed gear pumps axially disposed from each other and driven by a common shaft, wherein the diameters of the two gears of each pump set are of diiferent diameters so that the portion of fluid divided from a fluid stream entering the particular stage and carried around the periphery of one gear is combined with the fluid carried around the periphery of the other gear at a different point in the fluid stream causing a higher degree of mixing of the fluids.

A still further object of the invention is the provision of a blending pump having a plurality of modular stages, each being housed in a substantially transparent housing as to permit visual observation of the operation of the pump.

Another object of the present invention is to provide a blending pump including a plurality of dual gear pumps having a common driving means, and wherein adjacent pairs of gears are disposed in substantially parallel planes but displaced angularly from coextension with one another so that the operation of each stage can be more easily observed.

These and other objects of the invention are more fully set forth in the following detailed explanation having reference to the attached drawings in which illustrative embodiments of the invention are shown, not to limit the scope of the invention but in order that the principles of the invention might be more clearly understood.

It should be recognized that the embodiments shown are merely illustrative of preferred forms of the blending pump of the invention andthat many possible modifications thereto can be eliected Without departing from the principles of the invention.

In the drawings:

"ice

FIGURE 1 is an exploded perspective view of a two stage embodiment of the invention;

FIGURE 2 is a perspective View of the assembled blending pump shown in FIGURE 1;

FIGURE 3 is an enlarged sectional View taken along line 53 of FIGURE 2; and

FZGURE 4 is a side elevation View of a multi-staged embodiment of the present invention.

Now, with particular reference to the drawings wherein like numerals denote like parts among the several figures, a blending pump of the invention is illustrated generally at id. in the embodiment shown in FIGURES l3 the pump it; comprises a primary stage 12, a secondary stage 14 and an exit side cover plate 16. In a preferred form, the housings if; and 2d of the primary and secondary stages respectively, and the cover plate 16 are all formed from a substantially transparent tough plastic material such as polymethyl methacrylate (Lucite) or polyoxymethylene (Delrin), although for some applications where corrosion and wear may be of particular importance, other materials such as stainlesssteel can be used. The use of transparent material is preferred because it allows the operator to observe the operation of each stage of the pump and make any process corrections necessary as a F result of his observations.

As best shown in FIGURE 1, a substantially figure-S shaped recess is formed in surface of the exit side of each housing, the recess 22 in the primary stage housing 13 being of'a lesser depth than that of the recess 24 in the secondary stage 2% for reasons more. fully set forth hereinafter. The

recesses

22 and 24, although lying in substantially parallel planes, are angularly displaced from one another so that only one lobe of the primary stage recess 22 is coaxial with a lobe of the secondary stage recess 24-. A pair of intermeshing spur gears 26 is contained for rotation in the primary stage recess 22 and a second pair of intermcshing spur gears 28 is contained for rotation in the secondary stage recess 24. The larger diameter gear 36? and the smaller diameter gear 32 comprising the primary gear pair 26 have the same transverse width, both being substantially equal in Width to the depth of the recess 22. Likewise, the larger diameter gear 34 and smaller diameter gear 36 comprising the secondary ear pair 28 are each equal in width to the depth of the recess 24. It can thus be seen that because the secondary stage recess 2 is deeper than the primary stage recess 22 that the secondary gear pair 24 is wider than the primary gear pair 22 when all the gears used have teeth of approximately the same size, it will be seen that there is a greater inter-tooth volume in the gears of the secondary stage than in those of the primary stage, and that therefore the total inter-tooth carrying capacity of the gears of the secondary stage is greater than that of the first stage by a fixed amount.

The placement and diameters of the recesses 22; and 24 are such that the outer edges of the teeth of the gears carried therein are so nearly adjacent the sidewalls 38 of the recesses as to be in sliding contact therewith.

As best illustrated in FIGURE 1, the smaller gear 32 of the primary stage and the larger gear 34- of the sec ondary stage are removably keyed to a common drive shaft 40. The shaft 40 is journalled at its inner end in a shallow recess 4-2 formed in the inner surface or the cover plate 16 and extends through sealingly engaging openings 44 and 46 formed through the housings 18 and 29 respectively. The portion of the shaft 49 extending from the housing 18 may have a land 48 machined thereon as to receive the set screw of a driving pulley (not shown); The larger gear 36 of the primary stage is secured to a blind shaft 5i) so journalled at one end in a shallow recess in the inlet face the secondary stage housing fitlxand at the other end a shallow'recess formed in the floor of the recess 22.. The smaller gear 3-6 of the secondary stage is secured to a blind shaft 52 journalled at one end in a shallow recess 54- in the cover plate 16 and at the other by a closely fitting opening 56 formed in the secondary stage'housing centrally of the smallerv In the preferred embodiment of the invention shownin FIGURES 13, an inlet conduit 65 is formed in the primary stage housing 18 radially thereof as to communicate an opening 62 at the outer edge of the'housing 18 with the inlet side 64 of the gear pair 26. The conduit 6% may conveniently have interior threads 66 formed in the outer portion thereof as to receive an appropriately sized, threaded conduitrei from a fluid supply. The

exit side 7% of the primary stage 12 communicates with an axial conduit 77. extendingbetween the exit side ill of the primary gear pair 26 and the inlet 74 of the secondary gears pair 23.

A fluid inlet conduit '76 is formedin the secondary stage originating a the outer edge of the secondary stage housing 2% and extending radially inward thereof to intersect the axial conduit '79. The outlet 78 of -t e secondary gear pair 23 communicates with a mixture outlet conduit 80. formed through the cover plate 16. Similarly to conduit as, the conduits'i and 34 may have interior threads formed, in the outer portions thereof re spectively to;receive a conduit 82 from a second fluid supply and a conduit 84 to a mixture use or storage container.

The blendingpump It isconveniently assembled as by threading bolts 86 through openings formed through the pump axially thereof. A sufficient quantity of suitable noncontaminating sealing compound such as petroleum jelly maybe expressed onto the mating sulffaces ofthe housings l8 and 2t and exit cover plate 16 prior to the assembling of the pump for a more perfect seal between the stages. 7 J

As willreadily be seen, the blending pump of the in-. vention is quickly assemblabie and can easily be taken apart for cleaning, sterilizing and replacement or interchanging of parts.

A second embodiment of the invention is illustrated in FIGURE 4. This blending pump tilt? is similar in all respects to the-one shown in FIGURES 1-3 except that v the primary stage Hi2 and secondary stage 164 are ,suc-

ceeded by a plurality of additional stages 1696 each hav- I ing a slightly greater volumetric pumping capacity than the stage immediatelypreceding. As with the firstembodiment the gear pairs (not shown) in successive stages lie insubstantially parallel planes and'are angularly disposed from one another as to permit more easy visual inspection of each stage through the preferably transparent-housings 1th; and cover platerlltl. The drive shaft 112 is elongated as to operatively engage one gear of each intermeshing pair. and has a drive pulley 114 mounted thereon, connected as by an endless belt 116 to the output shaft 118 of a suitable motor. Because the pump of the. present invention comprises modular stages or units, any; number of stages having desired capacities may be as sembled with one another to blend desired amounts of a selected number of fiuidswith one another to produce a mixture of definite proportion. V The term fiuicls, as used herein is. intended to apply to pumpable gases, liquids or solids or any mixtures thereof. 7

OPERATION The operation of the embodiment shown in FIGURES 1-3 will now be described as to produce a foamed ice cream freeze mix, being mindful that the FIGURE 4 embodiment operates in asimila'r manner, but having additional stages.

Primary and secondary stages having the desired difference of volumetric capacity are selected and assembled as shown.

Theprimarystage inlet conduit fitlis connected I015 supply of liquid ice cream -mix, as through threaded conduit 68. This supply may be either a gravitationalv or pressurized feed. The secondary stage inlet conduit. 76 is connected in like manner to a source of air which may be in the nature of a vcntto the atmosphere or a pressurized air source. Themixture outlet conduit is connected to a receiver of foamed mix receiver, such;as an icecream freezing machine and the drive shaft 40, is,

engaged by the output shaft of an electric motor and caused to rotate in the direction of the arrow (FIGURE 3) ata desired speed. T be greater the speed, the greater willvbe the. volume of foamed mixture produced,

As best shown in FIGURES 1 and 3, the cream in the 'inlet conduit 66 is drawn at'the primary stage inlet 64 intothe inter-tooth cavities of the two gears Strand 32' of the primary gear pair as to substantially fill the cavities. The cream stream, thus continuously severedl intotwo substantially equal, parts, is conveyed aroundthe'nonintermeshing portion of the periphery of the primary gear pair, 26 and recombined. at the'outlet 70. However, because the gear '30 has a greater diameter than the gear 32 and because the rim speed of the two gears is the same, the cream'carried by the larger diameter gear 39 takes a greater amount of time to reach the. outlet 7t and is thereforerecombined with diiferent, quanta of cream in the cream stream from that=it was divided from at the inleto l. This mechanism serves to. cause a, greater homogenity of the mix metered by the first stage.

It can easily be seen that the amount of cream mix metered through the firststage, because cream mix is a liquid and therefore relatively incompressible, is substantially wholly dependenton the inter-tooth volume of the gears of the primary stage; The cream mix metered-by the primary gear pair .26isiforced by the gear pair 26 from the outlet 70, through the axial .conduit72 into the 7 inlet of the secondary stage.- stage gear pair 28 has a larger inter-tooth capacity .as. aforementioned, and because the secondary gear pair 28i is rotated at the same speed as the primary pair ,26, 21%

Because the secondary suction is created in the axialconduit 72ivwhich is dependent on the magnitude of the capacity diiferencebe The suction, beside drawingthe.

tween the two stages. mix from the primary stage outlet also constantly draws a fixed volume of air through the secondary stage inlet;

conduit 76. .'This airvis added to the fiuidmix in;the

axial conduit: at such a velocity as to beturbulently, mixed therewith causing the mixture tofoam. The foamed mix is divided at the secondary stages gear pair inlet and, conveyed around the, nonintermeshing periphery of the 1 gears 34 and 36 inthe inter-tooth cavities, Againgbew. cause the, inter-tooth cavities associated with each of the gears 34 and 36 is approximately the same size andbecause the gear 34 has a greater diameter than the gear 316,.approxl irnately half of the entering foamed mix is metered around each of the gears and the quanta of mix conveyed around the smaller gear 36 reaches the. secondary stage outlet 73 before that conveyed around the periphery of the larger gear 34 causing a greater amount-of mixing than would ibe'thecase if the-gears 34'and 36 were ofthe;

same diameter.

Iti can easily'be seen thatgtheamount of air added to: the mix in the second stageis dependent on the increase in the capacity of the secondistage over the first. 'In the preferred embodiment this increase is derived by increasing the thickness of the gears of the secondary pair and correspondingly increasing the depth of the recess 24 in the secondary stage housing 20. However, it is contemplated that this increase could be provided by other means, as by providing teeth on the secondary gear pair that would occupy less of the total volume between the root circle and addendum circle of each gear. The amount of air added by the second stage tothe mix metered by the first stage is also dependent on the pressure exerted on the air from outside the valve. Air being compressible, it can easily be seen that a greater amount of air will be added through the conduit 76 if it is connected to the pressure side of an air compressor rather than being open to air at one atmosphere pressure. Therefore, when the blending pump of the invention is employed to mix a plurality of fluids and at least one of the fluids is a gas, it is possible to vary the percent composition of the product of the blending pump by varying the inlet pressure of the gaseous constituent.

The foamed mixture metered by the scondary gear pair 28 is recombined at the outlet 78 and ejected from the pump through the exit conduit 89. It should be understood that in applications where more than two fiuids are blended that additional stages are interposed between the secondary stage and the cover plate and that the outlet 78 of the secondary stage would lead to the inlet of a tertiary stage having a capacity greater than the secondary stage by a proportion equal to the desired proportional addition of a third fiuid in the tertiary stage; A pump of the invention adapted to blend six constituents in fixed proportion is illustrated in FIG- URE 4.

The outlets of the blending pumps and 1% may be connected to foamed mix receivers such as a storage tank, or they may be connected to mixture users such as ice cream or frozen custard freezing machines. Because the blending pump of the invention is a positive displacement pump, it can be made to eject metered mixture from its outlet into a container having a considerable internal pressure.

Example I A supply of liquid ice cream mix is connected to the inlet of the primary stage of a two stage blending pump of the invention and metered thereby into the secondary stage which has twice the volume of the primary stage. The metered liquid mix traveling through the axial conduit between stages constantly primes the secondary stage, drawing air at 0 pounds gage pressure through the secondary stage inlet to mix with the liquid ice cream mixture. The two components become one foamy product as they turbulently mix in the axial conduit and travel around the peripheries of the secondary stage gears. The foamed product, discharged into a container having an internal pressure of pounds, gage, is consistently composed of /3 part liquid and /3 part air by volume (50 percent overrun) due to the compression of the air.

Example 2 A two stage blending pump of the invention is assembled as a secondary stage having three times the capacity of the primary stage. The inlet conduit of the primary stage is connected to a supply of noncar-bonated soft drink liquid and supply of carbon dioxide at 0 pounds, gage, is connected to the secondary stage inlet conduit. When the pump is operated, two volumes of CO will be metered into every volume of soft drink liquid and the frothy product, when ejected from the outlet of the second stage into a freezing compartment at 30 pounds, gage, contains /3 soft drink and /3 CO by volume. The product when semi-frozen is a soft drink product having a percent overrun.

6 Example 3 A three stage blending pump embodying principles of the invention is assembled from modular units as to have primary, secondary and tertiary stages of a volumetric capacity ratio of 126118. These stages are employed, as above, to accurately blend 1 part soft drink syrup, 5 parts water and 12 parts carbon dioxide respectively into a frothy mixture, and discharge the mixture into a pressurized freezing chamber to form a semifrozen carbonated soft drink product comprising 1 part syrup, 5 parts water and 3 parts CO by volume (i.e. a drink in semi-frozen state that has a 50 percent overrun). The compressibility of CO accounts for the reduction in its volume-trio proportion in the pressurized freezing chamber.

Although the individual stages have been illustrated as generally round, disk-like members, it should be realized that the shape of the outer periphery of each stage may be square, rhomboidal or any other shape.

It will now be realized that several preferred forms of the invention have been set forth which fully accomplish the objects set forth atthe beginning of this specification and the operation of these preferred forms has been set forth in great detail. However, those skilled in the art will realize that many omissions, additions and substitutions may be made with regard to the preferred forms shown and explained without departing from the principles of this invention as set forth herein and therefore the extent of the invention should be limited only by the spirit and scope of the appended claims.

What is claimed is:

1. Apparatus for effecting the blending of two fluid streams according to a predetermined proportion and for pumping the resulting fluid mixture comprising a first disk-like housing having a recess formed in one face thereof as to have two substantially circular interconnecting lobes of equal depth defined by a floor substantially parallel to the associated housing face, and sidewalls substantially perpendicular tothe floor of the recess, a pair of intermeshing spur gears mounted for rotation in said recess, each gear being of a thickness substantially equalling the height of said recess sidewalls and each of a width as to slidably engage the sidewalls; a fluid inlet conduit in the disk-like first housing extending radially between the outer edge of the housing and the recess at a point adjacent the intermeshing portion of the gears on that side of the intermeshing portion where the teeth of the two gears move away from one another during the rotating of the gears; a second disk-like housing having a first face abutting and sealingly engaging the last named face of the first housing and a second face having a recess formed therein as to have two substantially circular interconnecting lobes of equal depth defined by a floor substantially parallel to the second face of said second housing and sidewalls substantially perpendicular to the fioor of said recess, the recess in the second housing being deeper than the recess in the first housing by a percentage equalling the desired percentage addition of the second fluid; a second pair of intermeshing spur gears mounted on the second housing recess, each gear being of a thickness substantially equalling the height of said recess sidewalls and each of a width as to slidingly engage the sidewalls, a conduit in the second housing, extending axially thereof between the recess at a point adjacent the intermeshing portion of the second gear pair on that side whence the teeth of the two gears move away from one another during the rotating of the gears and the first stage recess at a point adjacent the intermeshing portion of the first gear on that side whence the teeth of the two gears move toward one another during the rotating of the gears, a second fluid inlet conduit in the disk-like second housing extending radially between the outer edge of the second housing and the axial conduit, intersecting said axial conduit intermediate the ends thereof; a disk-like cover plate having 37 a first face abutting and sealingly engaging the last named face of the second housing, and an outlet conduit extend ing axially through said cover plate, said outlet conduit communicating with, the recess of the second housing at a point adjacent the intermeshing portion of the second gear pair on that side whence the, teeth of the two gears move toward one another during rotation of the gears a 1 first fiuid directed intothe first "inlet conduit said first fluid being divided into two portions, conveyed around the non-,intermeshing portions of the first gear pair in the inter-tooth cavities thereof and ejected into the'axial conduit of the second housing, a second fluid being directed into the second inlet conduit, turbulently mixed with the first fluid inthe axial conduit, the resulting fluid mixture being divided into two portions, conveyed around the nonintermeshing portions of the first gear pair in the intertooth cavities thereof'and ejected from the second housing through the outlet conduit.

2. Apparatus as set forth in claim 1 wherein one spur gear of each spur gear pair has a substantially greater diameter than the other gear of the pair, whereby the portions of fluid conveyed around the gears of larger diameter recombine with different quanta of fluid conveyed around the gears of smaller diameter than the ones from which they were, divided.

3. Apparatus as set forth in claim 1 wherein one'spur' gear of each pair is secured to a single drive shaft for rotation thereon. 5

I 4. Apparatus as set forth in claim 1 wherein the first spur gear pair and the second spur gear pair are mounted for rotation in substantially parallel planes, one gear of each pair being secured for rotation ona single drive shaft extending. axially of said first and second housings, each of saidrhousings and said cover plate being comprised of substantially transparent material, the other gear first spur gear pairbeing angularly disposed from the other gear of the second spur gear as to facilitate complete visual inspection or" the operation of the apparatus. 5. Apparatus for effecting vthe blending of twofiuid streams comprising a first housing, a pair of intermeshing, counter rotatable spur gears mounted within said housing,

meansdefining-an inlet to and an outlet from said first gear pair in said housingsaid gear pair comprising a gear of larger diameter and a gear, of smallerdiameter,

means defining a fluid inlet insaid housing communicate,

ing with the inlet-of said geaiipair; a second housing, a pair of intermeshing counter rotatable spur gears mounted within said second housing, means defining an inlet to and. an outlet from second gear pair in said housing, said sec..

0nd gear pair being of a greater thickness than said firstge'ar pair and comprising a gear of largerdiameter and a gear of smaller diameter,:-a conduit extending between the outlet of the first gear pairand the inlet of the second gear-pair, means defining a fiuidinlet in the second'housr' ing,- said second fluidinlet communicating with the last a named conduit intermediate the ends thereof and with the exterior of said second housing; and means defining:

an outlet conduit extending from the outlet of the second gear pair. I p

6. Apparatus as set, forth in claim 5 wherein the first and second housings are substantially transparent, one 1 gear of each gear pair being secured for rotation to a single 7 drive shaft and the other gear of the first gear pair being angularly ,disposedcwith respect to the other; gear of the second gear. pair so as tofacilitate complete visual inspection of the operation of the apparatus.

References Cited by the Examiner UNITED STATES PATENTS CHARLES A. WILLMUTH, Primary Examiner.

GEORGE IMNORTH, Examiner.

Claims

5. APPARATUS FOR EFFECTING THE BLENDING OF TWO FLUID STREAMS COMPRISING A FIRST HOUSING, A PAIR OF INTERMESHING, COUNTER ROTATABLE SPUR GEARS MOUNTED WITHIN SAID HOUSING, MEANS DEFINING AN INLET TO AND AN OUTLET FROM SAID FIRST GEAR PAIR IN SAID HOUSING, SAID GEAR PAIR COMPRISING A GEAR OF LARGER DIAMETER AND A GEAR OF SMALLER DIAMETER, MEANS DEFINING A FLUID INLET IN SAID HOUSING COMMUNICATING WITH THE INLET OF SAID GEAR PAIR; A SECOND HOUSING, A PAIR OF INTERMESHING COUNTER ROTATABLE SPUR GEARS MOUNTED WITHIN SAID SECOND HOUSING, MEANS DEFINING AN INLET TO AND AN OUTLET FROM SECOND GEAR PAIR IN SAID HOUSING, SAID SECOND GEAR PAIR BEING OF A GREATER THICKNESS THAN SAID FIRST GEAR PAIR AND COMPRISING A GEAR OF LARGER DIAMETER AND A GEAR OF SMALLER DIAMETER, A CONDUIT EXTENDING BETWEEN THE OUTLET OF THE FIRST GEAR PAIR AND THE INLET OF THE SECOND GEAR PAIR, MEANS DEFINING A FLUID INLET IN THE SECOND HOUSING, SAID SECOND FLUID INLET COMMUNICATING WITH THE LAST