US2728495A - Liquid dispensing device and composition therefor - Google Patents

Description

Dec. 27, 1955 s. E. EATON LIQUID DISPENSING DEVICE AND COMPOSITION THEREFOR Filed April 19, 1951 IN VEN TOR. 514M051. fan/n20 4 TOA/ Unitfi tates Paton LIQUID DISPENSING DEVICE AND COMPOSITION THEREFOR Samuel Edward Eaton, Hingham, Mass, assignor to Arthur D. Little, Inc., Cambridge, Mass., a corporation of Massachusetts Application April 19, 1951, Serial No. 221,759

12 Claims. (Cl. 222-394) This invention relates to the art. of dispensing liquids from containers by internally-generated gas pressure, for example to self-propelled sprays and the like, and to apparatus and procedure for eflecting such dispensing. In particular, this invention has to do with the provision of a container in which are the liquidto be sprayed and a propellant therefor, said container being gas-tight and being provided with discharge-controlling orifice means,

.such as a valved nozzle, whereby the, liquid may be sprayed out as and when desired.

The liquid composition or product to be dispensed may be any of those which commonly are, or which conveniently can be, dispensed by atomizing or spraying means, such as insecticides, mothproofers and the like; paints, varnishes, and other coating materials; perfumes, deodorants, nasal sprays and other cosmetics and various other liquid pharmaceutical and other drug products; various liquid food-product coating materials, such as. syrups; and icings; fire extinguishing compositions; and, generally, liquid materialswhich are to be applied so as to adhere to and/or soak into surfaces and hence are ejected mainly as coarse sprays or jets rather than with fine atomization or vaporization of the spray or jet.

Self-propelled liquid sprays are now commonly made using solutions or emulsions of the propellant liquid and the liquid to be sprayed. The solution or emulsion is sprayed out in the form of a fine particle sized aerosol or mist, rather than the relatively coarse spray featuring droplets possible with the present invention. The spray of the prior art contains not only the desired liquid to be sprayed but also the propellant liquid. Although the latter generally vaporizes at once upon ejection and helps produce this fine spray, it is sometimes of an inflammable nature and hence a fire or explosion hazard, especially in confined spaces. Furthermore, the amount of propellant liquid is necessarily fairly large, being seldom less than and in some cases constituting the entire liquid phase (the material to be sprayed then being a solid dispersed or dissolved in the propellant liquid). The pressure within the container becomes quite high, since higher pressure is required to provide and propel the usual fine sprays now employed. Propellant liquids having very low boiling points are employed to attain these higher pressures, with the fineness of the spray being at least partly due to the volatilization of the propellant-liquid which is present in'the spray. The containers therefore must have considerable structural strengtha requirement which demands materials now in critically short supply, such as plastics and metal, commonly metal. Steel containers, when the material to be sprayed is aqueous and/ or contains an electrolyte, are also subject to corrosion.

Objects of the present invention include in particular the provision of liquid dispensing containers featured by internal propellant gas pressures, such as self-propellant sprays, using considerably less than the usual amounts of propellant, and lower, yet still effective, pressures within the container so that if desired, lighter-weight cans or ZflZhAdS Patented Dec. 27, 1955 glass containers may be safely used. Furthermore, the propellants of this invention are, as a practical matter, immiscible with, and are not emulsified with the liquid to be'sprayed, and are now non-inflammable and relatively non-corrosive, and of a greater specific gravity when in liquid phase than thatof the liquid to be sprayed. Hencefire and explosion hazards may be minimized, and, if metal containers are used, corrosion due to the propellantis greatly reduced. In fact, the preferred propellant of this invention. frequently appears, in itself, to inhibit corrosive action of the composition to be dispensed when used in metal containers. This is especially true with respect to the bottoms of such containers, due at least partly to blanketing thereof by pools of the propellants in liquid phase;

The containers filled in accordance with this invention therefore are provided with a three-phase system, two liquid and one gaseous. The liquid phases are the propellant, at the bottom of the container, and the liquid composition or product to be dispensed or sprayed, which floats above the propellant liquid. The gaseous phase is the vaporized propellant together usually with a minor amount of the other volatilized components of the systern. The liquid composition or product to be dispensed or sprayed may be a single liquid substance, or a mixture of liquids, or a solution or suspension of solid matter in one or more liquids.

This invention will be more fully understood by reference to the accompanying drawing, which shows a typical container in vertical section. The drawing shows a container 1 havingwalls ofsuitable strength for the intended purpose, and provided with a discharge tube or conduit 2 forming a passage having an intake opening near the bottom of the container but somewhat above the top level of the propellant liquid 3. Tube 2 terminates at the top in a nozzle 4, the fiuid flow to which is controlled by valve 5. Nozzle 4 is any suitable low pressure atomizing nozzle or simply an orifice capable of forming a jet; it requires no auxiliary air or gas flow through it to atomize or distribute or eject the escaping liquid. Pressure of ones finger or thumb on valve 5 opens the valve so that the liquid to be sprayed escapes through and is atomized by nozzle 4. When this pressure on valve 5 is removed, the valve is automatically closed by a spring 9, or by the pressure within the container, or both. The discharge controlling orifice means need not be a valved nozzle since where discharge of the entire contents of the container at one time is to be had, the discharge orifice at the outer end of the passage may be closed by a breakable seal to serve as the sole discharge control. The body of liquid composition or product to be sprayed is indicated by the'numeral 6. As the propellant 3 vaporizes, bubbles 7 of the resulting vapor rise through the body of the liquid composition or product 6 to form gaseous phase 8 which is under pressure. As the liquid composition is sprayed out through nozzle 4, more of propellant 3 vaporizes to fill the additional space above the body of liquid 6. The amount vaporized in any case is suflicient to create gaseous pressure enough to expel the liquid composition 6 from the container through tube 2 and nozzle 4.

The preferred propellant for the purposes of this invention is a fluorinated hydrocarbon, usually also ch10- rinated, of the types commonly sold under the trade names Freon or Genetron. The compounds of these types which are used herein (aside from any diluents which they may contain) all have the general formula CnHnzClyFa, wherein. n is a Whole number (usually 1 or 2), x is zero or a whole number, y is zero or a whole number, and z. is a whole number, and the sum of x, y, and. z is. equal to 2n+2. Typical of such compounds which are suitable are the following, with their boiling points in degrees centigrade:

Mixtures of-these compounds may be used. All of the propellant compounds used in this invention have a specific gravity greater than that of the liquid composit on or product to be dispensed. If the liquid composition or product to be dispensed has a specific gravity greater than that of water, the propellant liquid selected should have a still greater specific gravity. The boiling point of the propellant, at atmospheric pressure, must be below ordinary room temperature (about 20 0.), in order to insure effective vaporization under all ordinary condtions of operation.

When used in glass containers, the amount and nature of the propellant of this invention should be such as to provide, when entirely in the gaseous state, a volume from about 1.2 to about times that of the container, calculated at normal temperature and pressure (0 C. and one atmosphere absolute pressure), and a vapor pressure of the propellant at room temperature (20 C.) of between 1 p. s. i. g. and 100 p. s. i. g. Lesser amounts and pressures are generally ineffective to propel the material to be dispensed or sprayed properly and completely out of the container, while larger amounts and pressures are apt to cause glass fragments to fly forcibly in the event of accidental breakage of the bottle, due to a thoughtless users failure to take ordinary precautions in handling, such as careless dropping and rough tossing into metal trash cans and the like of gas-charged containers after discharge of liquid contents, particularly if, through carelessness, the container is at an elevated temperature. The particular range to be selected within the above limits will depend among other things upon the size of the glass container and upon the conditions of use. Small bottles, such as would be used for perfumes, can safely withstand the higher pressures within the above range better than larger bottles such as would be used for insecticides, for example. Bottles which would be kept at low temperatures, e. g. bottles of syrups or icings which would be kept in a refrigerator and used cold, could also safely contain propellants capable of producing such higher pressures better than could similar bottles, e. g. of insecticide sprays or aerosols intended for use in tropical climates.

If the containers are formed of materials somewhat stronger than glass, such as metal, but perhaps of appreciably thinner gauge and less strength than that previously used and thus being more prone to rupture at higher pressures, the above figures for volume and vapor pressure may be somewhat higher with the maximum pressure to be generated being dictated by the strength of the container.

The vapor pressure of the propellant at room tempera- 1 ture, when glass containers are used, may for example be around 5 p. s. i. g., or lower. The pressure employed depends also upon the type of delivery desired. For atomization, the pressure cannot be appreciably lower than around 2 p. s. i. g., assuming suitable nozzle design,

whereas for forming a simple jet, without appreciable the propellant which dissolves in the liquid composition or product to be dispensed escapes from the container during use until the liquid composition is practically exhausted, i. c. has dropped to the level of the bottom of the inlet of tube 2. Since the transition of the propellant from liquid to gaseous phase is therefore not accompanied by any appreciable loss of propellant, the container, when nearly exhausted, usually contains a major proportion of the original propellant in the gaseous form. This gas has a higher free energy content than that of the original propellant liquid, due to its absorption of at least a part of its heat of vaporization.

This emphasizes the desirability of keeping the quantity of propellant at a minimum consistent with effective delivery of the entire quantity of the liquid composition or product to be dispensed, since excessive quantities of propellant are very likely to lead to increased danger, in the event of accidental breakage of the container, as more and more of the propellant becomes vaporized. This is an especially important consideration when glass containers are used, since the danger of flying glass must be avoided. This danger is due not so much to any unprovoked rupture of the container, but to the forces released when the container is accidentally dropped, or struck sharply enough to shatter it.

The propellant may be introduced into the container in any suitable manner, for example by forcing it in through the valve 5 under high enough pressure to keep it in the liquid state, and after the liquid composition or product to be dispensed has been introduced, or by cooling it below its vaporization point and then putting it into the container which also may have been cooled. Other ways of introducing are shown in the examples which follow.

The following examples will serve to show further the several features of the present invention, and are to be construed as illustrative rather than limiting.

Example I 400 ml. of an aqueous moth-proofing compound containing 0.6 per cent sodium aluminum silicofluoride as active ingredient is introduced into a pint glass bottle. A test tube containing 3.2 ml. of the cold liquefied propellant (CClF2)2, is placed in the bottle so that no mixing occurs. The glass container is immediately closed with a cap fitted with a discharge tube, valve, and nozzle. The container is then inverted in order to mix the two liquids. During spraying of the moth-proofing compound the container should be kept in a more or less upright position so that the propellant will remain on the bottom. The bottom inlet of the discharge tube or conduit (which is represented by numeral 2 of the drawing) extends to between about one-eighth and one-sixteenth inch above the layer of liquid propellant at the bottom of the bottle. The quantity of propellant (1.23% by weight) is such that it will give on vaporization at room temperature and pressure a volume of about 1 /2 times the volume of the pint bottle, this amount being more than suflicient to expel all the contents. The initial pressure within the container is 13 p. s. i. g. at 70 F.

Example II grams of an aqueous deodorant is introduced into a four ounce phenolic resin lined tin coated aerosol can which is sealed with a cap fitted with a valved discharge means connected to a tube. 5 grams of the propellant, a mixture of about 70% CHaCCIFz and the balance CClzFz and CClaF, is added under pressure through the tube and a nozzle is then fitted to the end of the tube. The quantity of propellant (5% by weight) is such that it will give a volume of gas when vaporized at room temperature and pressure of about ten times the volume of the can. The initial pressure within the container is 30 p. s. i. g. at 70 F.

It is preferable to exclude air from the container, so that the pressure within the container may be maintained when metal containers are used, so as to reduce the corrosion which is promoted by the presence of the oxygen of the air. Exclusion of air is accomplished when the container is filled, for example by use of vacuum, or by flushing the container with an inert condensible gas such as Freon or steam, before or after introducing the propellant and the liquid to be sprayed.

What is claimed is:

1. A self-propelled liquid dispensing device comprising a gas-tight container having relatively easily rupturable walls, a contained 3-phase fluid system comprising a liquid medium to be dispensed and a propellant present in both gaseous and liquid form and which in said liquid form is substantially immiscible with and of greater specific gravity than said liquid medium, said propellant having a boiling point not greater than about 20 C. and being present in an amount such that when entirely in the gaseous state and calculated at C. and one atmosphere absolute pressure it will occupy a volume from about 1.2 to about times the volume of the container, the gaseous phase of said propellant being under pressure, above said liquid medium, a conduit having a passage extending from a point within said container above, and near, the bottom of said liquid medium to a low pressure discharge orifice at a point outside of said container, and means for controlling the flow of fluid from within said container through said conduit passage to said discharge orifice.

2. A self-propelled liquid dispensing device in accordance with claim 1 wherein the walls of said container are of glass.

3. A self-propelled liquid dispensing device in accordance with claim 1 wherein the walls of said container are of thin metal.

4. A self-propelled liquid dispensing device as defined in claim 1 in which the propellant is a fluorinated hydrocarbon.

5. A self-propelled liquid dispensing device as defined in claim 1 in which the propellant is a fluorinated and chlorinated hydrocarbon having from one to two carbon atoms per molecule.

6. A self-propelled liquid dispensing device as defined in claim 1 in which the propellant is a fluorinated hydrocarbon and in which the liquid medium to be dispensed contains a silicofluoride as an active ingredient.

7. A self-propelled liquid dispensing device comprising a gas-tight container having relatively easily rupturable walls, a contained 3-phase fluid system comprising a liquid medium to be dispensed and a propellant present in both gaseous and liquid form and which in said liquid form is substantially immiscible with and of greater specific gravity than said liquid medium, said propellant having a boiling point not greater than about 20 C. and being present in an amount such that when entirely in the gaseous state and calculated at 0 C. and one atmosphere absolute pressure it will occupy a volume from about 1.2 to about 5 times the volume of the container, the gaseous phase of said propellant being under pressure, above said liquid medium, and means for conveying said liquid medium from a point within the body thereof to a point outside said container for ejection at said latter point, said propellant being selected from the group consisting of fiuorinated, and chlorinated and fluorinated, low molecular weight saturated aliphatic hydrocarbons containing not more than two carbon atoms.

8. A self-propelled liquid dispensing device as defined in claim 7 in which the liquid medium is an aqueous medium.

9. A self-propelled liquid dispensing device as defined in claim 7 in which the liquid medium is an aqueous medium containing a silicofluoride and the propellant is a chlorinated and fluorinated hydrocarbon.

10. A self-propelled liquid dispensing device as defined in claim 7 in which the liquid medium is an aqueous medium containing sodium aluminum silicofluoride, and

the propellant is tetrafluoro-dichloroethane in an amount of about 1.23% by weight of the composition.

11. A self-propelled liquid dispensing device comprising a gas-tight container having relatively easily rupturable walls, a contained 3-phase fluid system comprising a liquid medium to be dispensed and a propellant present in both gaseous and liquid form and which in said liquid form is substantially immiscible with and of greater specific gravity than said liquid medium, said propellant having a boiling point not greater than about 20 C. and being present in an amount such that when entirely in the gaseous state and calculated at 0 C. and one atmosphere absolute pressure it will occupy a volume of at least about 1.2 times the volume of the container, the gaseous phase of said propellant being under pressure, above said liquid medium, and means for conveying said liquid medium from a point within the body thereof to a point outside said container for ejection at said latter point, said propellant being selected from the group con-' sisting of fluorinated, and chlorinated and fluorinated, low molecular weight saturated aliphatic hydrocarbons containing not more than two carbon atoms.

12. A self-propelled liquid dispensing device comprising a gas-tight container having relatively easily rupturable walls, a contained 3-phase fluid system comprising a major proportion of a liquid medium to be dispensed and a minor proportion of a propellant present in both gaseous and liquid form and which in said liquid form is substantially immiscible with and of greater specific ,gravity than said liquid medium, said propellant having a boiling point not greater than about 20 C. and being present in an amount such that when entirely in the gaseous state and calculated at 0 C. and one atmosphere absolute pressure it will occupy a volume of at least about 1.2 times the volume of the container, the gaseous phase of said propellant being under pressure, above said liquid medium, and means for conveying said liquid medium from a point within the body thereof to a point outside said container for ejection at said latter point, said propellant being selected from the group consisting of fluorinated, and chlorinated and fluorinated, low molecular weight saturated aliphatic hydrocarbons containing not more than two carbon atoms, the quantity and characteristics of said propellant being so adjusted as to be insufiicient to cause rupture of the container walls or dangerous propulsion of fragments in the event of accidental breakage.

References Cited in the file of this patent UNITED STATES PATENTS 710,674 Fassman Oct. 7, 1902 854,317 Tyree May 21, 1907 1,614,532 Mobley Jan. 18, 1927 1,901,960 Goss Mar. 21, 1933 1,990,499 Odell Feb. 12, 1935 2,070,167 Iddings Feb. 9, 1937 2,128,433 Rotheim Aug. 30, 1938 2,302,497 Johansson Nov. 17, 1942 2,305,286 Ward Dec. 15, 1942 2,313,930 Gebauer Mar. 16, 1943 2,340,328 Jones Feb. 1, 1944 2,345,081 Ward Mar. 28, 1944 2,351,376 Ward June 13, 1944 2,358,986 McGovran et al Sept. 26, 1944 2,362,472 Dreisbach et al. Nov. 14, 1944 2,375,215 Davis May 8, 1945 2,440,915 Roehr May 4, 1948 2,524,590 Boe Oct. 3, 1950 2,536,231 Simanton Jan. 2, 1951 2,539,929 Roberts Jan. 30, 1951 FOREIGN PATENTS 4,286/98 Great Britain Feb. 21, 1898 OTHER REFERENCES Lesser: Article in October 1949, issue of Drug and Cosmetic Industry, pages 396-398; 470-473.

Claims (1)

1. SELF-PROPELLED LIQUID DISPENSING DEVICE COMPRISING A GAS-TIGHT CONTAINER HAVING RELATIVELY EASILY RUPTURABLE WALLS, A CONTAINED 3-PHASE FLUID SYSTEM COMPRISING A LIQUID MEDIUM TO BE DISPENSED AND A PROPELLANT PRESENT IN BOTH GASEOUS AND LIQUID FORM AND WHICH IN SAID LIQUID FORM IS SUBSTANTIALLY IMMISCIBLE WITH AND OF GREATER SPECIFIC GRAVITY THAN SAID LIQUID MEDIUM, SAID PROPELLANT HAVING A BOILING POINT NOT GREATER THAN ABOUT 20* C. AND BEING PRESENT IN AN AMOUNT SUCH TAHT WHEN ENTIRELY IN THE GASEOUS STATE AND CALCULATED AT 0* C. AND ONE ATMOSPHERE ABSOLUTE PRESSURE IT WILL OCCUPY A VOLUME FROM ABOUT 1.2 TO ABOUT 5 TIMES THE VOLUME OF THE CONTAINER, THE GASEOUS PHASE OF SAID PROPELLANT BEING UNDER PRESSURE, ABOVE SAID LIQUID MEDIUM, A CONDUIT HAVING A PASSAGE EXTENDING FROM A POINT WITHIN SAID CONTAINER ABOVE, AND NEAR, THE BOTTOM OF SAID LIQUID MEDIUM TO A LOW PRESSURE DISCHARGE ORIFICE AT A POINT OUTSIDE OF SAID CONTAINER, AND MEANS FOR CONTROLLING THE FLOW OF FLUID FROM WITHIN SAID CONTAINER THROUGH SAID CONDUIT PASSAGE TO SAID DISCHARGE ORIFICE.

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