US2950031A - Liquid stream dispensing pressure package for high viscosity liquids - Google Patents

Description

AU8- 23, 1950 R. H. ABPLANALP ETAL 2,950,031 LIQUID STREAM nIsPENsING PRESSURE PACKAGE FOR HIGH VISCOSITY LIQUIDS Filed oct. 23, 1957 /ZQ y I y l ROBERT HC EEN-rolas E E @M ME;

LIQUm STREAM DISPENSING PRESSURE PACK- AGE FOR HIGH VISCDSITY LIQUIDS Robert H. Abplanalp, Bronxville, and Joseph C. Pizzurro,

Scarsdaie, NX., assignors to Precision Valve Corporation, Yonkers, N.Y., a corporation of New York Filed Oct. 23, 1957, Ser. No. 691,874 4 Claims. (Cl. 222-394) This invention is for dispensing high viscosity liquids from pressurized containers.

There has developed within the past few years an eX- tensive market for pressure packed materials, including aerosols, which have met with remarkable public approval because of the ease and facility of dispensing liquid products so packaged. This packaging is peculiarly adapted for the application of liquids in linely divided spray form.

ln the packaging of such materials, the active ingredient to be dispensed is placed in a can or other container and there is introduced into the can a propellant, such as Freon or the like. The can is generally provided with a manually operable discharge valve having an associated dip tube which extends to the bottom of the can so that, when the valve is opened by manual pressure on the valve stem, the material is discharged, due to its pressurized condition.

Lotions, insecticides, lacquers, deodorants, pharmaceutical preparations and a wide variety of other products have heretofore seen so packaged and have given highly satisfactory results for the reason that all of them are of relatively low viscosity and it is possible to discharge them in spray form through the employment of a propellant under pressure. However, there are also many liquid products of relatively high viscosity which it would be desirable to dispense from a pressurized package, such as waxes, high viscosity hand lotions, shampoos, vanishing creams7 shaving creams, dentrices and other relatively high viscosity products in paste or cream form. These particular products must have such relatively high viscosity to function properly for their intended purposes for, if they are diluted to a point where their viscosities are Suiciently low to permit pressure dispensing, as carried out under prior practice, their eiciency or usefulness is correspondingly lowered. With such products it has heretofore been the uniform practice to package them in collapsible tubes or in containers with screw tops or cork closures which may be removed to permit of slow pouring of that portion of the contents which it is desired to apply, although in some cases pumps have been aS- sociated with such products to pump them from the containers in which they are marketed.

We have sought over an extended period to find some way in which such relatively high viscosity liquids could be pressure packed in such manner that they would be protected against deterioration in the package, but could be delivered in the form of a ribbon or stream of predetermined length or duration, according to the will of the operator. We found that if attempt is made to so package a high viscosity liquid according to conventional practice, there results a phenomenon known as cavitation. This is evidenced by the formation of a cavity which, as the material is discharged, progressively extends from the surface thereof down to and linally reaches the lower end of the dip tube, whereupon all of the propellant is discharged from the can without carrying with it the active ingredient. This results in the discharge from the can of only a relatively small portion of its contents, leaving the remainder in the can without sucient pressure therein to discharge the same. The phenomenon of cavitation is increasingly greater as the viscosity of the active ingredient isgreater, so that with relatively heavy gels, oils, vanishing and other creams, tooth paste and similar materials, the present day procedure will develop, during a prolonged dispensing operation, a relatively deep hole or cavity in the active ingredient, due to the fact that the active ingredient is such that it wil not rapidly dow to fill in such cavity. Thus in the common aerosel container, where the dip tube is extended from the valve to one corner of the can, a relatively small portion of such active ingredient will be dispensed before the propellant is released.

Some fairly light creams and products of like consistency are used only at periodic intervals with suicient intervening time forthe material in the can to attain a level after each use. However, there are other materials which if used successively, as by different members ofthe family, may not surface level with sufficient promptness to avoid serious cavitation between successive uses. In other instances and for other materials each use requires a dispensing of a considerable portion of a package without suliicient intervening periods between uses to permit of a .return to a surface level. In any event it is desirable with all pressure packed products to eliminate any such cavitation that would allow under any circumstances a release of the propellant until substantially all of the contents of the can is dispensed.

The object of the present invention is to provide a novel package whereby a'much greater portion of the material can be Withdrawn before serious cavitation occurs and it is the purpose of this invention to provide a method and means whereby even a continuous dispensing operation will bring about the release of substantially all of the contents of the can.

' As a practical matter, it is universally the case that the high viscosity liquids should be dispensed in the form of a ribbon or stream without frothing or foaming and for this reason we preferably employ as a propellant an inert gas, such, for example, as nitrogen, argon, neon, crypton, xenon, helium or radon, or a combination of one or more of them, for these gases are little, if at all soluble in the high viscosity liquids to the packaging of which this invention is directed.

In the preferred practical form, the package of this invention conveniently comprises the usual can or other container, having any appropriate or conventional discharge valve to which is aixed a dip tube coaxially of the can. This tube should be sufficiently rigid to maintain it in substantially coaxial condition or appropriate means should be provided to hold it in such position. The tip tube is provided at its lower end with a radial baie, the peripheral edge of which is not higher than the lower end of the dip tube and said baffle is so arranged within the can that said peripheral edge is relatively close to the bottom of the container, so as to provide a shallow annular outlet mouth between said peripheral edge and the bottom of the can, located to discharge substantially all of thecontents of the can before anyv cavitation which may occur can release the propellant through the dip tube.

With this arrangement, the active ingredient in the container, in order to reach the passage through the dip tube, must pass through said shallow outlet mouth at the very bottom of the can and our tests have thoroughly demonstrated that any cavitation which occurs is generated in the form of an annular cavity, coaxial with the tip tube. This is in marked contradistinction to the con- Ventional exible dip tube package wherein maximum cavitation occurs at a point directly above the laterally disposed lower end of the dip tube and develops with much more rapid progression downwardly along one side of the can wall than at the opposite side thereof to form a deep hole in the active ingredient which reaches the open end of the dip tube and permits escape of the propellant after only part of the contents of the container have been dispensed.

Experience has shown that through the employment of the present invention, a continuous dispensing operation, carried on until cavitation reaches the peripheral edge of the bathe, will effect the discharge of substantially al1 active ingredient in the container.

Features of the invention, other than those adverted to, will be apparent from the hereinafter detailed description and appended claims, when read in conjunction with the accompanying drawing.

The accompanying drawing illustrates different practical embodiments of the invention, but the constructions therein shown are to be understood as illustrative, only, and not as defining the limits of the invention.

Fig. 1 is a central vertical section perspective through a conventional aerosol type package embodying a conventional dip tube, showing the eiect of cavitation when it is attempted to dispense high viscosity liquids therefrom.

Fig. 2 is a like view showing a packaging embodying the present invention.

Figs. 3, 4 and 5 show -modied forms of baifle which we may employ.

Fig. 6 is a bottom plan view of the baille.

Referring to the drawing, 1 designates a conventional can which may be of any desired shape, but is shown as having the usual domed bottom 2. The can is sealed by a cup or cover 3 on which is supported any appropriate type of discharge valve having a valve stem 5, which, when operated, will unseat the sealing member of the valve. Robert H. Abplanalp Patent No. '2,631,814 shows a highly satisfactory valve which is now widely used.

To the lower end of the valve is secured the usual dip tube 6 which, in accordance with common practice, is a flexible, generally plastic, tube. This tube extends from the valve to the bottom of the can and near the side wall thereof. In short, Fig'. 1 shows a conventional aerosol type of package, illustrated herein to demonstrate the difference between the present invention and such prior practice. The can is charged with an active ingredient 7 and in the space 8 is contained a propellant which is generally in the form of a compressed gas or a liquid and gas, as the case may be,

When the active ingredient 7 is of high viscosity so that it will not flow readily, the opening of the sealing member of the valve 4 will permit gaseous pressure in the chamber 8 to force the active ingredient upwardly through the dip tube, valve and valve stem 5, to be discharged therefrom through any suitable iinger piece or cap common in the art. However, experience has shown that with high viscosity liquids which have a low rate of flow, the discharge of these liquids results in progressive cavitation, indicated by the progressive cavities c, c1, c2, c3, shown in dotted lines, as the material is forced downwardly in a highly localized manner to the lower end of the dip tube, as shown in Fig. 1.

These cavities are really nothing more than holes of substantially pocket form which progress and deepen until they reach the lower end of the dip tube 6 and thus release the propellant without the dispensing of further active ingredient. It will thus be apparent from Fig. 1 that only a relatively small amount of the material 7 may be discharged before .the propellant will be released according to the prior practice as shown in this figure. The same result occurs if the dip tube of Fig. l is made straight and is arranged so that its lower end is located at the center of the bottom of the can except that a deep hole is formed in the center of the container.

A package according to the present invention is shown in Fig. 2. It embodies the same COIltIle; a Vef .at ing a valve and a valve stern as shown in Fig. 1. However, it differs insofar as the dip tube is concerned, from the structure of Fig. l. In the structure of Fig. 2 a dip tube 11 is secured to the valve and is preferably arranged coaxially of the can. This dip tube is provided at its lower end with a circular baille 12 arranged coaxially of the can. The dip tube may be made sufficiently rigid to hold the bafe in this position or the bathe may be otherwise' so maintained. In any event the bafe has a diameter a plurality of times the diameter of the dip tube i1 and in practice it may conveniently radially extend substantially midway of the distance from the axis of the container to the lateral wall thereof. If a bafe of this latter size is employed, it may be too large to be introduced through a normal opening at the'top of the can, but in practice such baiile may be made of any suitable resilient material, such as polyethylene, nylon or the like, so that it may be temporarily bent or distorted while introducing it into the can, being adapted to return to its normal shape after introduction.

An important feature of this invention is that the peripheral edge of the baille must be positioned close to the bottom of the can, so as to provide between its periph ery and the container bottom an annular inlet mouth 13 through which material to be discharged from the containervmust pass before it ows to the dip tube and through that tube through the discharge valve. Shallow ribs or projections are preferably formed on the under side of this baie, to seat upon the bottom 2 of the container and thus act as spacers to determine the height of the outlet mouth. The provision of this shallow annular outlet mouth, radially spaced an appreciable distance from the dip tube and from the lateral wall of the can, makes possible satisfactory performance of this invention in the dispensing of high viscosity liquid materials.

It wll be noted from Fig. 2 that with the arrangement therein shown, the cavitation is not localized. -In fact the conditions which would tend to cause it are distributed throughout the circumference of the bafe, so that cavitation proceeds, as Vindicated in the dotted lines in this figure, to produce successively lower annular cavities d, d1, d2, d3, d4 and d5, which extend entirely around the dip tube and develop substantially uniformly across the entire diameter of the can as the liquid material is continuously discharged. With the same high viscosity active ingredient shown in Fig. l, the structure shown in Fig. 2 will dispense from the can very much greater quantity of material than can possibly result in the structure of Fig. 1, before the propellant is released.

In fact, as the active ingredient is dispensed, the entire surface of such active ingredient will recede within the container, so that by the time any portion of the propellant is released, such surface has receded to approximately the plane of the peripheral edge ofthe baffle. It therefore follows that the position of this battle with respect to the bottom of the container will largely control the amount of material that can be dispensed from the container. If the baffle were placed at any considerable distance from the bottom of the can, a large portion of said ingredient would be left in the container after the propellant had escaped and this would beco-me waste as such material could not thereafter be dispensed.

It is of course desirable that substantially all of the material be dispensible and to make this possible the baile should be placed so that its peripheral edge is below the lower end of the dip tube proper and said peripheral edge should be located as closely as possible to the bottom 2 of the container to form the shallow inlet mouth 13. The spacing between said peripheral edge and the bottom of the can should be fairly close but should be suiicient to meet the requirements of the 1nternal diameter of the dip tube which, for the dispensing of high viscosity liquids, is preferably of somewhat larger `internal diameter than that normally employed for the aerosol dispensing of low viscosity liquids, such as insect and other space sprays and the like. The shaping of the body of the baffle is not of particular importance so long as its periphery has a relatively close spacing to which reference has been made. However, in the domed bottom container shown in Fig. 2, a satisfactory form of baiiie is shown as having the same general curvature as the bottom 2 of the can. This curvature may, however, be greater as shown in Fig. 3 or the bale may be of conical form as shown in Fig. 5. In flat bottom containers, the baffle may be made as shown in Figs. 2, 3 or 5, or may be flat as shown in Fig. 4. If the can is circular, the baflie is preferably circular as illustrated in Fig. 6.

In the preferred form of the invention, we make the bafe imperforate as shown in the drawings for it has been our experience that a bafe so constructed operates to the best advantage.

Experience has shown that the present invention is a very pronounced forward step in this art. lt permits of the practical dispensing of pressurized liquids of viscosities which could not possibly be so dispensed under prior practice and it insures the discharge from the can of a maximum amount of material therein which, in practice, means substantially the entire contents of the can.

As hereinbefore stated, it is generally essential that the propellant be a neutral gas, i.e., a gas which will not chemically react, dissolve or dilute the active ingredient in the can. Nitrogen will satisfactorily fulfill the purposes of this invention and experience has shown that even with very high viscosity liquids, the gaseous pressure of the propellant ordinarily need not exceed 90 pounds per square inch at room temperature. Such pressures of a neutral gas operate effectively in the dispensing of these products without frothing or foaming and which issue from the valve stem button or cap in the form of a stream or ribbon, depending upon the shape of the outlet used.

When the present invention is employed for normally spaced periodic uses, it has been found that it Will function in the manner described to dispense practically all of the contents of the can as stated and, even if the valve is continously held open, a similar result will accrue, although there may be still left a little of the material in the can.

rThe foregoing detailed description sets forth an illustrative form of package well suited for performing the method of this invention which comprises, generally speaking, the application of propellant gaseous pressure to the surface of high viscosity material in a confined space and drawing off said material from an annular zone approximately midway between the axis of said space and the lateral wall thereof through a shallow outlet mouth at the bottom of said space.

In the preferred method of performing this invention, the outlet mouth through which the material `is withdrawn from a space is positioned approxi-mately midway between the axis of the space and the lateral wall of that space. This is not critical. However, it is important that the diameter of that outlet mouth be fa plurality of times greater than the internal :diameter of the dip tube, so as to eect the drawing off of the material from an annular zone which is spaced sufficiently far from the axis of the tube and from the lateral wall of the space to produce annular cavitation which will eiect substantially the entire cross sectional area of the material in the space. While the package hereinbefore described is satisfactory to carry out this method, we are aware that other forms of package may be employed for performing the same.

The part 1 has been hereinbefore referred to as a can or container which, according to the glossary of the tart, may be of metal, glass or plastic shell in which a product is pressure packed for pressure dispensing.

The foregoing detailed description sets forth the invention in its preferred practical forms, but the invention is to be understood as fully commensurate with the appended claims.

Having thus fully described the invention, what we claim as new and desire to secure by Letters Patent l. A dispensing package for gaseous pressure packed high viscosity liquids, dentrifices, creams and like materials comprising: a container having an upwardly domed bottom, an outlet valve for said container, a dip tube connected to said outlet valve and extending to a point substantially central of the container and near the bottom thereof and there provided with a radially disposed upwardly domed baie the chordal plane of the periphery of which intersects the domed bottom of the container, said bafle being of much greater diameter than the dip tube with the periphery of said baffle spaced from the bottom to provide between them a shallow inlet mouth, whereby substantially all the material within the container may be dispensed before cavitation permits the escape of gaseous pressure through said mouth.

2. A dispensing package according to claim 1, wherein the baffle and the bottom are curved on substantially the same center.

y3. A dispensing package for gaseous pressure packed high viscosity liquids, dentriees, creams and like materials comprising: a container, an outlet valve for said container, a dip tube connected to said outlet valve and extending to a point substantially centrally of the oontainer and near the bottom thereof and there provided with a radially disposed baffle extending to approximately midway of the distance from the tube to the side wall of the container, with the periphery of the baffle positioned below the lower end of the tube and closely adjacent the bottom wall of the container to form therewith a shallow mouth through which substantially all of the contents of the container may be dispensed before cavitation permits the escape of gaseous pressure through said mouth.

4. A dispensing package according Vto claim 3, wherein the baffle -is provided with projections engaging the bottom wall of the container to space the periphery of the bafe therefrom.

References Cited in the file of this patent UNITED STATES PATENTS 362,459 Neil May 3, 1887 1,333,547 Johnson Mar. 9, 1920 2,128,494 Morrow Aug. 30, 1938 2,137,786 Schlosser Nov. 22, 1938 2,412,434 Thompson Dec. 10, 1946 2,715,481 McGhie et al Aug. 16, 1955 2,723,200 Pyenson Nov. 8, 1955 2,746,647 Efford et al May 22, 1956 2,781,152 VanSlyke Feb. 12, 1957 2,811,390 Kiraly Oct. 29, 1957

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