US3430819A - Method and article for the packaging of aerosol products - Google Patents

Description

March 4, 1969 W, MOONA 3,430,819

MZTI- ZL AND ARTICLE FOR THE PACKAGING OF AEROSOL PRODUCTS Original Filed Jan. 27, 1964 Sheet of 2 IN VEN TOR.

M14 04M MOOA/AA/ March 4, 1969 w. MOONAN I 3,430,819

METHOD AND ARTICLE FOR THE PACKAGING OT AEROSOL PRODUCTS Original Filed Jan. 27, 1964' Sheet 3 012 INVENTOR.

r L Mag/AM Mow/4M Wflk/ /W 30 i 26 MMM H ii United States Patent 3,430,819 METHOD AND ARTICLE FOR THE PACKAGING OF AEROSOL PRODUCTS William Moonan, Shaker Heights, Ohio, assignor to Sprayon Products, Inc., Bedford Heights, Ohio, a corporation of Ohio Original application Jan. 27, 1964, Ser. No. 340,261, now Patent No. 3,335,765, dated Aug. 15, 1967. Divided and this application Mar. 29, 1967, Ser. No. 640,765 US. Cl. 222402.1 12 Claims Int. Cl. B67c 3/06; 1065b 37/00 ABSTRACT OF THE DISCLOSURE Aerosol cans are partially filled by the manufacturer with the required amount of liquified propellant gas and at least one but not all of the constituents of a material to be dispensed, such as a solvent or thinner for a paint or lacquer that is to be dispensed. The cans are provided with normally closed discharge valves and the pressurized cans are then placed in commerce. The cans are completed as aerosol packages by or on behalf of the ultimate users by subsequently injecting into them the balance of the materials to be dispensed, such as paints or lacquers of especially blended colors. Thus, each individual can, of many cans that were substantailly identical when shipped to the manufacturer, can be used to dispense a different custom blended color of paint or lacquer, if desired.

Cross reference to related application This application is a division of my copending application Ser. No. 340,261, filed Ian. 27, 1964, now Patent No. 3,335,765.

This invention relates to the packaging of pressurized products and more particularly to methods, articles and apparatus whereby a product to be dispensed, such as a paint, lacquer or other material that is to be dispensed in aerosol form, can be injected into an aerosol can that already contains the liquified propellant gas that is used to discharge the contents of the can. The invention is described herein particularly as it is adapted to loading 1 paints, lacquers, varnishes, enamels and like coating materials (hereinafter referred to as paints and the like) into aerosol cans, but it is to be understood that the invention may also be used in connection with other materials, such as insecticides, lubricants, medicines, cosmetics and the like if that is desired.

Paints and the like are sold widely in aerosol cans. conventionally, these materials are packaged in aerosol cans by placing the required amount of the vehicle and solvents for the paint or the like, together with the pigments, into aerosol cans that have open tops. Then, according to one method, the open top of the can is closed and sealed by a closure member that carries the valve that controls the discharge of the aerosol spray from the can. Thereafter, the required amount of liquified propellant gas, such as dichlorodifluoromethane or other ap propriate halogenated hydrocarbon is added to the can by forcing it in the liquid state through the discharge valve. According to another method, propellant gas is added to the cans in the liquid state through the open tops of the cans and then the closure member carrying the discharge valve is applied to the top of the can. Both types of operations require rather complex and expensive equipment.

The demand for paints and the like in many different colors and shades as well as the practice of custom blending of colors makes it impractical for the usual dealer, such as a paint or hardware store, to keep in stock loaded aerosol cans containing paints of all of the colors and types that may be requested, Also, aerosol paints and the like are used widely for the touching up of damaged areas of automobiles, appliances, furniture and the like; if an article has been finished in a color blended to suit an individual customers preference, it is desirable to furnish the customer with an aerosol can containing the specially blended paint so that the customer can touch up damaged areas if necessary. There are also other products involving specially prepared formulations that could conveniently be dispensed from aerosol cans, but which are not so dispensed at present because, so far as I am aware, there is no economical and convenient way presently available for filling one can or a few cans to meet a particular requirement.

Accordingly, general objects of the present invention are the provision of an improved method whereby it is possible economically and efficiently to fill small numbers of aerosol cans with specially blended or formulated materials such as paints and the like, and the provision of pressurized containers that can be completed as aerosol cans containing the material to be dispensed, such as paint or the like, of proper consistency for spraying, by injection of the material in unreduced consistency, into the cans.

Other objects and advantages of the invention will become apparent from the following description of a preferred form thereof, reference being made to the accompanying drawings in which:

FIGURE 1 illustrates an aerosol can of a well-known type that is adapted to be filled by the method and apparatus of the present invention;

FIGURE 2 is a perspective illustrating an apparatus made according to a preferred form of my invention with an aerosol can in position for filling therein;

FIGURE 3 is a perspective, on a slightly smaller scale, illustrating the apparatus of FIGURE 1 with some of the parts disassembled;

FIGURE 4 is a vertical sectional view, on an enlarged scale, through the apparatus of FIGURE 2;

FIGURE 5 is an enlarged section detail showing the top of a can such as illustrated in FIGURE 1 and embodying a known aerosol discharge valve, and illustrating the engagement between the apparatus of the present invention and the valve;

FIGURE 6 illustrates one of the disposable cylinder liners used in the apparatus;

FIGURE 7 is a fragmentary section taken along line 7-7 of FIGURE 4, and FIGURE 8 is an elevation showing the same parts;

FIGURE 9 is a fragmentary vertical sectional view showing an apparatus embodying a modified form of piston that is enclosed in a disposable sleeve.

The apparatus of the present invention is particularly adapted to inject materials into aerosol cans of conventional types, for example, cans such as illustrated at 10 in FIGURE 1. Can 10 has a cylindrical body 11 and an upwardly convex bottom 9, the bottom being convex in order to give it strength to withstand the pressure within the can. The upper end of the can body 11 is reduced in diameter as at 12, leaving an opening which is closed by a closure cap 13 that is crimped and sealed to the upper edge of the can body.

Cap 13 supports a discharge valve 14 that may take any convenient form, a preferred form of valve being illustrated on an enlarged scale in FIGURE 5. The valve is normally closed but may be opened by means of a plastic actuating cap 15 having a hinged flap 16 that engages a valve actuating pin 17; when the flap is depressed by the users finger the pin 17 is also depressed and opens the valve as explained in greater detail below. When the flap is depressed, the pressure of the propellant gas within the can causes the contents of the can to flow upwardly through the flexible plastic dip tube 18 and the valve 14 and finally to be discharged from a spray orifice 19 carried by the cap. Upon release of the flap, the valve automatically closes. When cans of this type are filled at the factory, the material to be sprayed, such as a paint or the like, is placed in the can before the closure cap 13 is secured to the top of the can. Then as noted above, the closure cap can be secured to the can and the propellant in liquified form forced through the valve into the can or the propellant in liquified form can be added to the can before the closure cap is secured to the top of the can. In either event, the level of the material in the can is then approximately at the level of the dotted line A in FIGURE 1. After the closure cap 13, to which the valve 14 has been secured, has been crimped to the top of the can and the filling of the can completed, the plastic actuating cap 15 carrying the actuating pin 17 is placed on the upwardly projecting body 20 of the valve 14.

According to the present method, cans intended for filling in accordance with the present invention are charged with an initial charge consisting of a desired amount of liquified propellant gas, such as dichlorodifiuoromethane and a solvent for the material to be dispensed at the factory perferably before the cap 13 is crimped to the can. The can is closed by the cap 13 carrying the valve 14. The aerosol package then can be completed at any subsequent time by injecting the material to be dispensed into the can through the valve 14, preferably by the use of the apparatus of the present invention. In typical formulations, the liquified propellant gas is about fifty percent by weight of the contents of the can, but since the propellant has a substantially greater specific gravity than the usual paint or the like, in typical formulations the liquified propellant is a little more than forty percent by volume and the product a little less than sixty percent of the contents of the can. According to the preferred method, part or all of the solvent (the term solvent as used herein includes blends of two or more solvents) for the material to be dispensed such as paint or the like is also placed in the can; this is ordinarily done before the can is closed and before the liquified propellant gas is added to the can; the liquified gas is added either before or after the can is closed by a cap 13 carrying a valve 14.

Loading the solvent at the factory is advantageous because paints and the like as ordinarily sold must be reduced by the addition of solvent before they can be properly sprayed. By adding, at the factory, the solvent that would otherwise have to be added to the paint or the like as supplied by the manufacturer to reduce it to spraying consistency the following benefits accrue: (1) If solvent were not added at the factory, it would be necessary to reduce the paint or the like as it comes from the paint manufacturer with a solvent before injecting the paint or the like into the aerosol can. The preferred method eliminates this step. (2) The correct amount of solvent can be added by automatic machinery under carefully controlled conditions in the factory. (3) The use of a correct solvent that is compatible with the propellant gas can be assured. (4) The addition of the solvent reduces the vapor pressure in the aerosol can from, for example, about pounds per square inch gage with dichlorodifluoromethane to about 50 to 53 pounds per square inch gage. This reduction in pressure makes it possible to use less expensive and more readily available cans than would be required for the higher pressure and lessens the pressure that must be employed to inject the balance of the material into the aerosol can through the dispensing valve. (5) Los of solvent by evaporation during the operation of finally filling the cans is minimized. (6) The volume of material that must be injected into the aerosol can through the dispensing valve is substantially reduced.

A typical 6 ounce aerosol can containing a lacquer to be sprayed will contain about 42 gm. of lacquer as supplied by the lacquer manufacturer, 42 gm. of solvent and 84 gm. of dichlorodifiuoromethane. The materials have different specific gravities, the liquified propellant having the greatest. By volume, the propellant is a little more than 40% of the liquid content of the can, the solvent a little over 30% and the unreduced lacquer a little less than 30%. With such a formulation, dotted line B in FIGURE 1 shows the approximate level of propellant and solvent. If propellant only is placed in the can at the factory, the level is about as indicated by line C. Line A indicates the level after the lacquer has been injected into the can. A typical 6 ounce can of a spray enamel contains about 55 gm. of enamel as supplied by the manufacturer, about 30 gm. of solvent and about 84 gm. of dichlorodifluoromethane. Here, the dichlorodifiuoromethane constitutes a little over 40% by volume of the liquid content of the can, the solvent about 22% and the enamel a little more than 35%. It will be seen that in both of these typical cases, if the solvent is added to the can at the factory the amount of material that must be injected into the can to complete the product is substantially reduced. Furthermore, the greater viscosity of the paint or the like before it has been reduced to spraying consistency makes it easier to inject into the can and reduces leakage problems as compared to the same material that has been reduced with the required amount of solvent.

It is evident that cans containing the initial charge consisting of propellant and solvent are complete articles of manufacture that can be sold to paint dealers, hardware stores, large users of aerosol products and others to be used in the production of complete pressurized packages of materials, ready for use. The actuating cap 15 and the pin 17 are not slipped over the body 20 of the valve before the cans are shipped from the factory. Instead, the cans are supplied to the users of the present invention without the actuating caps and pins in place, these being supplied separately. The cans then can be made into complete aerosol packages simply by injecting the particular material to be dispensed, including any required additional solvents, dispersing agents, vehicles, or the like, into the can through the valve 14 against the pressure within the can and putting the actuating caps and pins in place on the valve bodies.

The present invention provides a relatively simple and economical apparatus whereby paints and the like, as well as other materials to be dispensed from pressurized containers can be injected easily and rapidly into cans of type described above. As shown in FIGURES 2, 3 and 4 of the drawings, an apparatus according to the invention comprises a base member indicated in general at 25 and having diverging leg portions 26 that are provided with vertical ribs 27. The ribs merge into a curved, substantially semi-cylindrical, upwardly extending portion 28 at the forward end of the apparatus where the legs 26 are joined together by a web 29. The web provides a support for a can 10 disposed within the recess provided by the upwardly extending portion 28, in position to be filled. The rear ends of the legs 26 and the forward end of the curved portion 28 are provided with feet 30 for supporting the apparatus on a counter, bench or the like.

The base 25 is arranged to support a cylinder and piston mechanism that is adapted to be actuated by hand to force material into a can against the resistance offered by the valve 16 and against the pressure within the can. To this end, a horeshoe-shaped member 31 is secured to the top of the upwardly extending portion 28. Member 31 is provided with a circular recess 32 that is dimensioned to fit the supporting flange 33 of a cylinder member 35. Cylinder 35 has a main, working bore 36, a conical, tapered portion 37 and a depending, externally tapered connecting portion 38 having a bore 39 that is adapted to surround the upwardly projecting body 20 of valve 14.

The cylinder 35 is held in position within the recess 32 of the horseshoe-shaped member 31 by a pair of locking levers 40 that are pivotally mounted on the member 31. These may be positioned in a locking position, as shown in FIGURE 2, where their ends 40a overlie the upper surface of the flange 33, or in a release position as shown in FIGURE 3 where the levers are swung toward each other so that their ends 40a clear the flange 33 to permit the entire cylinder mechanism to be removed from the support. At the upper end of the cylinder 35 there is an outwardly extending flange 41 that supports a cylindrical member 42 that constitutes a reservoir for material to be injected into the can 10.

In order to make it unnecessary to clean the cylinder 35 or the reservoir 42 when changing from one material to another or from one color or shade of paint or the like to another, as well as to provide for a substantially fluid-tight connection between the cylinder 35 and the valve, disposable liners 45 are provided for insertion into the cylinder 35 and the reservior 42. As shown particularly in FIGURES 3, 4 and 6, each liner comprises a reservoir portion 46 terminating in a sloping bottom 47 that is joined to a more steeply sloping conical portion 48 that is connected to a downwardly extending cylind'rical portion 49. The liners are preferably composed of a translucent material and when such liners are to be employed the wall of cylindrical member 42 is preferably slotted as at 43 and provided with graduations 44 so that the amount of material placed in the reservior portion 46 can be determined with the required degree of accuracy. The cylindrical portion 49 fits closely within the main bore 36 of the cylinder 35 and constitutes, in effect, the working portion of the cylinder. At the lower end of the cylindrical portion 49 there is another inwardly sloping conical portion 51, that joins with a connecting portion 52 that fits closely within the re duced bore 39 of member 35 and surrounds the body of the valve.

In order to make a substantially leakproof connection between the connecting portion 52 of the liner 45 and the exterior of the body 20 of the valve 14, the interior of the connecting portion 52 is provided with an inwardly projecting annular rib or head 53 (see FIGURE 5) that is dimensioned to make sealing engagement with the cylindrical exterior surface of the valve body. Since the liners are preferably composed of polyethylene or another similar slightly yieldable plastic material, and since the connecting portion 52 is supported against expansion in radial directions by the bore 39 of cylinder 35, the rib 53 can be dimensioned so that it must be deformed slightly when it is pushed over the body 20 of the valve. In this manner sufficiently high unit pressures can be developed between the rib and the exterior surface of the valve body substantially to prevent leakage around the exterior of the valve body, even under the rather high fluid pressures that are required to force material into the cans.

The reason that substantial pressures are required will be evident from the consideration of FIGURE 5 which shows the apparatus in use in conjunction with a valve 14 of a known type that is described and claimed in United States patent application Ser. No. 157,296, filed Nov. 22, 1961 in the names of John G. Ellis, Vernon C. Groth and John Hall. The valve body 20 has an internal bore 55 that communicates with the dip tube 18. A valve member 56 is disposed within the bore beneath a valve seat 57 that is formed in the bore. The valve member 56 is urged into sealing engagement with the valve seat 57 by the pressure of the propellant gas Within the can and also by the force exerted on it by a valve spring 58. The valve is thus in the nature of a check valve that is normally closed to prevent discharge of the contents of the can, but which can be opened by external fluid pressure in excess of the pressure within the can, thereby permitting material to be injected into the can. The valve member 56 is shown in FIGURE 5 as being displaced downwardly away from the seat 57 this occurs when material is being forced into the can. In practice a pressure of several hundreds pounds per square inch is required to open the valve and to force the valve member 56 out of sealing engagement with the seat 57 against the fluid pressure and the force exerted by the spring. The reason for this, of course, is that the area of the valve member 57 exposed to pressure of the material being forced into the can is relatively small so that even though the spring pressure is not excessive, the fluid pressure required to open the valve against the action of the spring and the fluid pressure within the can is substantial.

A piston 60 that is dimensioned to make a close working fit within the inner surface of the cylindrical portion 49 of the liner 45, which constitutes the working portion of the cylinder, is utilized to force material from the reservoir 46 into the can 10. In the embodiment shown in FIGURES 3 and 4, the piston consists of a rod of uniform diameter throughout substantially its entire length, the lower end of the rod being shaped as shown at 61 to conform to the conical tapered portion 51 of the liner. The upper part of the rod is guided in a cylinder head 62 that is detachably secured to the upper end of the reservoir 42 as by bayonet lock 63.

In order to provide for actuation of the piston 60, a bracket 65 is secured to the upright portion 28 of the base 25. An upwardly extending link 66 is pivoted to the bracket as at 67 and an actuating lever 68 is pivoted to the upper end of the link 66 as at 69. Lever 68 preferably extends through a bifurcated portion 71 at the upper end of piston 60 and is pivoted thereto by a removable pin 72. Preferably, the pin is provided with a projection 72a (FIGURES 7 and 8) so that the pin can only be inserted or removed when the keyhole slots 72b and 720 in the bifurcated end portion 71 and lever 68 are aligned, which occurs only when the piston and the lever are in their uppermost positions as shown in FIGURE 7. A convenient hand grip 73 is provided at the free end of the lever. In use, this is grasped by the operator as shown in FIG- URE 2. Downward movement of the piston is limited by engagement of the ends of a ball 75, which is set into. the piston, with the top of the upwardly projecting boss 76 of the cylinder head 62, but the ball is located so that in the assembled apparatus the tapered portion 61 of the piston engages the tapered portion 51 of the liner before the ball engages the boss 76. Upward movement of the piston is limited by engagement of a similar ball 78 with the bottom surface of the cylinder head 62. When the piston is in its upper position as shown in FIGURE 4, the tapered bottom end 61 of the piston is opposite the upper end of the cylindrical portion 49 of the liner leaving an annular clearance space between the piston and the cylindrical portion 49 so that material in the reservoir portion 46 of the liner can flow into the cylindrical portion 49 when the piston is at the top of its stroke. When the piston is at the bottom of its stroke the lower tapered end of the piston engages the correspondingly tapered portion 51 of the liner. Thus each stroke of the piston injects substantially all of the material within the cylindrical portion 49 of the liner into the can 10 through the valve 14 and by successive strokes of the piston, substantially all of the material in the reservoir can be injected into the can.

As noted above, it is necessary to develop substantial pressure in order to force material from the cylinder into the can. This is accomplished with the present apparatus without the exertion of undue force by the operator, because in a typical device, the piston 60 has an area of approximately one half square inch and the lever system multiplies the force exerted by the operator on the handle by about ten times. Thus, a downward force of about to pounds on the handle is ordinarily entirely adequate to force material from the cylinder into the can through the valve 15.

At the upper limit of its stroke, the piston clears the upper end of the working portion of the cylinder and thus the piston itself acts as the inlet valve for the pump that is made up of the piston and cylinder assembly. The valve 14 acts as the outlet or discharge valve for the pump. In operation, on the downward stroke of the piston, the material within the cylindrical portion 49 is forced into the bore 55 of the valve body 20; leakage around the exterior of the valve body is prevented by the bead 53. The pressure of the material displaces the valve member 57 downwardly against the act-ion of the spring 58 and the material under pressure flows through the internal bore 55 of the valve and the dip tube 18 into the can 10. When downward movement of the piston is stopped by engagement of bottom 61 of the piston with the portion 51 of the liner, the operator raises the handle, lifting the piston 60. When this takes place, the valve 14 closes immediately, the valve member 56 moving into. engageemnt with the seat 57 under the influence of the spring 58 and the pressure within the can 10. Raising the piston reduces the pressure within the cylindrical portion 49 and as soon as the bottom end of the piston 60 clears the upper end of cylindrical portion 49 as shown in FIGURE 4, material flows rapidly from the reservoir 46 into the portion 49, ready to be forced into the can 10 by a subsequent downward stroke of the piston. The liner is prevented from moving upwardly with the piston by engagement of the upper edge of the reservoir portion 46 of the liner with the under side of the cylinder head 62. The arrangement is such that by a comparatively small number of strokes of the piston 60, the required amount of material, such as the pigments, the vehicle, and some of the solvent of a paint or the like can be injected quickly and easily into a can.

In operation, initially the cylinder head member 62 is removed from the cylindrical reservoir 42, the levers are swung to release position, the cylinder 35 is removed from the horseshoe-shaped supporting member 31 and the cylinder head 62 and piston 60 are completely separated from the cylinder. A clean disposable liner is then inserted into the cylinder. The valve 20 of a can to be filled is inserted into the bore 39, these parts ordinarily being wrung together because of the tight fit between them, the head 53 making sealing engagement with the exterior of the valve body. Then the subassembly of the can 10, the disposable liner 45 and the cylinder 35 are positioned on the flat web 29 of the base as shown in FIGURE 4. The cylinder 35 then is locked in position by moving the levers 40 into locking position as shown in FIGURE 2.

The required quantity of the material to be injected into the can is then poured into the reservoir 46. The material fills the cylindrical portion 49 and the lower portion of the reservoir 46, the amount of material being conveniently measured by the graduations 44, the level of the material in the reservoir portion being visible through the slot 43 and the translucent wall of the liner. Next, the piston 60 is inserted in the cylinder, the cylinder head is secured to the top of reservoir 42, the handle 73 is secured to the piston by the pin 72 and the handle pumped up and down a few times until the lack of resistance to the downward stroke of the piston indicates to the operator that substantially all of the material within the reservoir 46 of the liner 45 has been injected into the can 10. The piston is then raised to its uppermost position and the pin 72 withdrawn to disconnect the piston from the handle. As noted above in the preferred form of apparatus this can only be done when the piston is in its raised position and thus disengaged from the cylindrical portion 49 of the liner. The levers 40 are then swung to the releasing position and the subassembly comprising cylinder 35, liner 45 and can 10 is removed from the horseshoeshaped support 31. The filled can is then removed from the subsassembly. This is preferably done with the subassembly upside down to minimize the amount of material that may be left on the exterior of the valve and to prevent such material from running into the closure cap 13. The assembly is completed by positioning a plastic actuating cap 15, carrying a pin 17, on the valve body 20. After this has been done, the valve is opened, with the can right side up, by means of the actuating cap until the small amount of injected material remaining in the dip tube 19 is discharged. Finally, the can is turned upside down and the valve held open until gas, rather than liquid, is discharged. The package is ready for use, except that with most materials the can should be shaken before use in order thoroughly to mix the contents.

If additional cans containing the same material are to be produced, the operations are repeated, using the same liner. Several cans can be filled without requiring a new liner 45.

If it is desired to inject a different material into a can, the liner 45 is thrown away after use and a new one inserted in the cylinder 35. Also, the piston 60 is wiped clean, using a solvent if necessary. Since the piston is smooth and since only the lower portion of the piston comes into contact with the material to be dispensed, this is not a difiicult task. The previously described operations are then repeated with the new liner.

If it is desired to eliminate substantially entirely the necessity of cleaning any of the parts, a modified form of piston as shown at 60a in FIGURE 7 may be employed. In this modification, the lower end of the piston rod is turned down to a slightly reduced dimension as shown at and a disposable sleeve 81, preferably composed of a plastic material, such as polyethylene, having a thickness corresponding to the reduction in radius of the piston 60 so that the external diameter of the sleeve 81 makes a working fit with the internal diameter of the cylindrical portion 49 of the liner 45, is slipped onto the piston rod. Sleeve 81 preferably has a flange 82 for case in handling. The lower portion of the sleeve conforms to the shape of the end of the piston and the shape of the portion 51 of the liner 45 so that the operation of the piston 60a with the sleeve on it is just the same as the operation of the piston 60 previously described. The only difference is that when it is desired to change materials being injected into cans not only is the liner 45 replaced, but also the sleeve 81 is removed from the piston 60a and replaced with a new sleeve. With this form of the apparatus it is not necessary, in ordinary circumstances, to clean any of the parts of the apparatus when changing from one material to another.

From the foregoing description it will be seen that the invention provides a simple and effective method whereby materials to be dispensed can be rapidly and easily loaded into aerosol cans which already contain an initial charge consisting of the liquified propellant gas and the solvent required to reduce the material to be dispensed to proper consistency for spraying. The preferred method is particularly advantageous in the case of paints and the like. Aerosol cans made according to the invention and containing solvent and propellant are also of great utility, because cans containing the same kinds and the same percentages of propellant and solvent can be produced economically in large quantities and these then can be used at any subsequent time with available or specially blended paints or the like to produce complete packages containing many different types, colors and shades of paints and the like. The apparatus is relatively inexpensive to manufacture and requires no particular skill to use. Since the apparatus does not require any complicated cleaning operations when changing from one material to another, it can be used effectively to produce one or a few cans of various different materials, such as paints and the like of different colors, in a comparatively short time. The invention greatly reduces the inventory of completed aerosol cans containing materials such as paints or the like that must be kept in stock by a dealer in or large user of aerosol products and gives the dealer much greater flexibility and better ability to supply the needs of his customers.

Those skilled in the art will appreciate that various changes and modifications can be made in the invention without departing from the spirit and scope thereof. The essential characteristics of the invention are defined in the appended claims.

I claim:

1. A method of preparing an aerosol container to dispense a material requiring a solvent to reduce it to a proper consistency to be discharged in aerosol spray form from the container, including the step of providing the container with a normally closed discharge valve and the step of placing in the container an initial charge consisting principally of liquified propellant gas and solvent for the material to be dispensed, the solvent being compatible with the propellant and the total volume of the propellant and solvent being substantially less than the total volume of the container, whereby material that is too viscous for proper spraying from an aerosol container may subsequently be injected into the container under pressure against the pressure of the propellant within the container at a different time and place to a users requirement to make up the complete charge of the container, the solvent in the initial charge being sufiicient to reduce the material to proper consistency for aerosol spraying and the propellant in the initial charge being sufficient for the complete charge.

2. A method according to claim 1 wherein the material is a paint or the like.

3. The method of filling an aerosol container with a material to be dispensed which includes the steps of placing in the container an initial charge consisting principally of the required amount of liquified propellant gas and a substantial amount of a solvent for the material to be dispensed, providing the container with a normally closed discharge valve, and thereafter injecting the material to be dispensed into the container under pressure.

4. The method according to claim 3 wherein the discharge valve is openable by external fluid pressure substantially in excess of the fluid pressure within the container, and the material to be dispensed is injected into the container through said valve under pressure sufiiciently greater than the pressure within the container to open said valve.

5. The method of filling an aerosol container with paint or the like which includes the steps of placing an initial charge consisting principally of the required amount of liquified propellant gas and a substantial amount of a solvent for the paint or the like in an aerosol container, closing the container except for a normally closed discharge valve, and thereafter completing the charge by injecting a paint or the like into the container against the pressure of said propellant gas within the container.

6. The method according to claim 5 wherein the valve is openable by external fluid pressure substantially in eX- cess of the fluid pressure within the container, and the paint or the like is injected into the container through said valve under pressure sufficiently greater than the pressure within the container to open said valve.

7. The method of filling a plurality of aerosol containers with paints and the like of several different colors which includes the steps of providing a plurality of aerosol containers each having an open upper end, placing an initial charge consisting principall of the required amount of liquified propellant gas and a substantial quantity of a solvent for the paints or the like to be dispensed in the container through the open end thereof, closing the container except for a normally closed discharge valve, said valve being openable by external fluid pressure substantially in excess of the fluid pressure within the container, and thereafter injecting a paint or the like of a desired color .into each individual container through the discharge valve of that container under pressure sufficiently greater than the pressure within the container to open said valve.

8. As an article of manufacture, a normally closed container adapted to withstand substantial internal pressures, said container having within it an initial charge consisting principally of a sufficient quantity of liquified propellant gas to discharge the contents of the container and a substantial quantity of a solvent for the material to be dispensed from said container under pressure by said propellant gas, said container also having means through which the material to be dispensed can be injected into said container against the pressure of the propellant gas within the container.

9. As an article of manufacture, a normally closed container adapted to withstand substantial internal pressures, said container having within it an initial charge consisting principally of a sufficient quantity of liquified propellant gas to dscharge the contents of the container and a substantial quantity of a solvent for the material to be dispensed from said container under pressur by said propellant gas, said container also having a normally closed discharge valve through which the material to be dispensed can be injected into said container against the pressure of the propellant gas within the container and through which the contents of the container can be discharged.

10. As an article of manufacture, a normally closed aerosol container adapted to be charged with a paint or the like, said container having within it an initial charge consisting principally of a sufficient quantty of lquifled propellant gas to discharge the contents of the container and a substantial quantity of a solvent for the paint or the like to be dispensed from said container under pressure by said propellant gas, said container also having means through which the paint or the like to be dispensed can be injected into said container against the pressure of the propellant gas within the container.

11. As an article of manufacture, a closed aerosol container adapted to be charged with a paint or the like, said container having within it an initial charge consisting principally of a sufficient quantity of liqufied propellant gas to discharge the contents of the container and a substantial quantity of a solvent for the paint or the like to be dispensed from said container under pressure by said propellant gas, said container also having a normally closed discharge valve through which the paint or the like to be dispensed can be injected into said container against the pressure of the propellant gas within the container and through which the paint or the like can be discharged from the container.

12. As an article of manufacture, a closed aerosol container adapted to be charged with a paint or the like, said container having within it an initial charge consisting principally of a sufiicient quantity of liqufied propellant gas to discharge the contents of the container and a quantity of a solvent for the paint or the like to be dispensed from said container under pressure by said propellant gas, said container also having a normally closed discharge valve at the top thereof through which the paint or the like to be dispensed can be injected into said container against the pressure of the propellant gas within the container and through which the paint or the like can be discharged from the container, the solvent being present in sufiicient quantity to reduce the paint or the like to a consistency which is suitable for spray ig, and a dip tube extending 2,881,808 4/1959 st rmain 222402.16 X within said container from said valve to a point adjacent ,273,606 9/ 1966 ONeill 141-20 X the 30mm Said wntainer- ROBERT E. REEVES, Primaly Eucaminer.

References Cited 5 HADD S. LANE, Assistant Examiner. UNITED STATES PATENTS US. Cl. X.R.

2,684,806 7/1954 McBean 1413 X 1413, 103; 53-37

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