GB1562000A

GB1562000A - Pressurized barrier container

Info

Publication number: GB1562000A
Application number: GB2128777A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1976-06-08
Filing date: 1977-05-20
Publication date: 1980-03-05
Also published as: IT1077206B; AR215138A1; CA1092069A; ES229111Y; JPS52150808A; MX147890A; JPS6323061B2; DE2722265A1; ES229111U; FR2354260B1; CH625180A5; IL52158A; FR2354260A1

Abstract

The dispensing container is provided for substances whose minimum viscosity at room temperature is 10,000 cps, but can rise to 500,000 cps or more. It has a pressure container with a dispensing valve (15). To open the dispensing valve, a hollow valve shaft (22) is pivoted in an elastic valve body (23). As a result, an aperture (32) is produced on the valve seat (26), through which aperture the substance to be dispensed can emerge via passages (28) and the shaft (22). This design of the dispensing valve allows such a large cross-sectional area for the throughflow that, despite low pressure of the propellant, a sufficiently large output through the valve (15) is guaranteed. Since the starting pressure must not exceed 2.81 atm, the pressure container can be of thin-walled design and be made of plastic, for example. This allows a considerable cost reduction. <IMAGE>

Description

(54) PRESSURIZED BARRIER CONTAINER (71) I, GEORG BERNARD DIAMOND, of Anthony and Woodglen Roads, Glen Gardner, New Jersey, United States of America, a citizen of the United States of America, do hereby declare the invention, for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a self-contained sealed pressurized barrier container sealed at the bottom and having a discharge valve at the top and a piston in the container serving as a gas-tight sealing barrier defining two chambers, one chamber communicating with the valve and containing a product for discharge at the pressure of a propellant within the other chamber.

The present invention particularly relates to containers for dispensing viscous products at an initial or charging pressure of only 6 to 40 psig, depending generally on the degree of viscosity of the product.

The invention is concerned particularly with products having a minimum viscosity of 10,000 cps but whose viscosity may be as high as 500,000 cps or more; and provides articles of manufacture in the form of valved pressurized containers of low pressure and hence of practically complete safety.

A novel form of discharge valve is disclosed which affords such a large cross-sectional flow area that a satisfactory rate of flow through the valve is attained despite the low propellant pressure. By reason of the reduced pressure, the wall of the container, when of metal, can be greatly reduced in thickness as compared to pressurized containers charged at 100 psig or higher, so that in addition to the lower cost of the reduced pressure, still further economy results from the use of small weights of metal, while at the same time wastage of metal is reduced. Similar economies are effected in the case of container walls made of plastic, laminates, and other materials including paper having surfaces impervious to liquids and gases.

In order to understand the invention, it is necessary first to consider the Regulations of the U.S. Department of Transportation as given in Tariff No. 30, entitled "Hazardous Materials Regulations of the Department of Transportation", including "Specifications for Shipping Containers".

The above regulation in Section 173.306 recognizes two types of pressure systems for metal containers.

1. For compressed gases, the container must withstand pressures of three times the pressure at700F.

2. For liquefied gases, the container must withstand one and one-half times the equilibrium pressure at 1 300F.

In determining the pressure requirements for barrier containers, account must be taken of the fact that the initial volume in the container not filled with product is about one-third of the total volume, so that if compressed gas is used, the initial pressure is three times the final (minimum) pressure. For example, if for a given product, a minimum pressure of 33 psig is needed (and this is also, of course, the final pressure), an initial pressure of 99 psig is required and the container must withstand a pressure of three times 99 or 297 psig. Heretofore, inert gas propellants, when used, were of this magnitude, i.e., 99-100 psig.

When a liquefied propellant is used in order to maintain 33 psig at 70 F, it will have a pressure of ca. 100 psig at 1300F, and the container will have to withstand a bursting pressure of ca.

150 psig. To maintain an average of 66 psig at 70 , a bursting strength of 250 psig will be needed.

Valved pressurized containers have for the most part been designed for the discharge of atomized sprays of low viscosity fluids or for the discharge of foaming low viscosity fluids.

In either case, the use of initial pressure at 700F of ca. 35 psig for liquefied gases (volatile liquids) or 100 psig for compressed gases was necessary, in order to obtain atomization or foaming. (The use of lower pressure liquefied gases in glass containers for the atomization of perfumes and the like required the use of highpriced propellants and valves).

When the use of barrier pressure dispensers for viscous fluids started some twenty years ago and up to the present time, the only available valves and containers were the small orifice valves and high pressure containers and these have been and are still in use today. The use of these containers made it necessary to warn the consumer against leaving the containers ex posed to sunlight and against throwing them into incinerators to open fires because of the danger of explosion. The prior containers, therefore, had to be made of rigid heavy gauge metal which increased their cost of production and transportation, and also made it difficult to eliminate denting and the by-pass or escape of the propellant.

According to the invention, products of high viscosity of, say 10,000 cps and above, may be packaged in a container at initial compressed gas pressure of ca. 6-40 psig at 700F or initial liquefied gas pressures of ca. 6-24 psig at 70 F The 6 psig compressed gas requires a bursting strength of three times or 18 psig, and the 6 psig liquefied gas requires a bursting strength of one and one-half times the pressure at 130 or 60 psig. The 40 psig compressed gas requires a bursting strength of 120 psig, and the 24 psig liquefied gas also requires a bursting strength of 120 psig. Containers of the present invention accordingly do not have a bursting strength higher than 120 psig. Preferably the propellant used is one that attains a maximum pressure of only about 90 psig at 1300F.

Since a compressed gas at an initial pressure of 40 psig gives a final pressure of ca. 13 psig, the use of liquefied gas at 13 psig would give the same final flow characteristics. The bursting pressure required for 13 psig liquefied gas is 75 psig, but if the liquefied gas is used in a novel way, described below, the bursting pressure required can be reduced even further.

According to a further feature of the invention, the quantity and type of liquefied gas to be used are calculated and determined, so that it is completely evaporated before the 130"F temperature is reached, whereupon it then acts as compressed gas, giving a lower pressure at 130 F, and above, than would otherwise be reached (i.e., with a continuing supply of liquid propellant), and therefore allowing even thinner walls for the package and even greater safety.

By way of example, and in accordance with the invention, there is employed, for a 6 fluid oz. container, a quantity of a volatile liquid fluorocarbon propellant, such as "Freon" (registered Trade Mark), less than 4 g. within the skirted piston, described hereinafter, and having a volume of about 2 oz., in contrast to the 7 to 10 g. employed in current practice, for the 6 oz. can, the amounts varying somewhat, depending on the specific fluorocarbon. Similar reductions in the amount of a volatile liquid hydrocarbon or other liquid propellant can be made in accordance with the present invention for the purpose stated.

The limited quality of volatile liquid propellant can be mixed with air, nitrogen or carbon dioxide, which on becoming mixed with the maximum amount of vapour originating in the liquid propellant, will yield a mixture of a gas and vapour having only the incremental increase in pressure per degree of increase in temperature, according to the gas laws. Hence, when temperature rises, the liquid propellant is completely evaporated at a pressure which is considerably below the legal limitations on pressures.

Also, according to the invention, valves of increased flow-through cross-section are used, while the container is made of much thinner metal than heretofore, similar to the containers for beverages, or a combination of metal foil and cardboard, or of plastic or laminates of cardboard and plastic film can be used, so that the cost of a valved container of 6-8 oz.

capacity is in the neighbourhood of 10-12 cents (U.S. currency) in contrast to the cost of 17-21 cents for the present-day valved container. In fact, a 16 oz. valved container would cost only about 13 cents, as compared to about 25 cents for a present-day valved container of equal volume, if such were available, which it is not, owing to the prohibitive cost. Since the retail cost to the consumer is from 3 to 5 times the manufacturing cost, savings to the consumer of from 20 cents to 35 cents per package are feasible.

If the cost of discarding dented containers and malfunctioning containers is also included, an even greater saving is possible since the invention also minimizes malfunction and denting.

In contrast to prior pressurized containers, with or without barrier, the invention accordingly presents the following 1. Economic advantages--lower cost 2. Safety advantages-lower pressure 3. Ecological advantages, i.e., less material is used per container, and the use of metals and plastics is conserved.

4. Denting does not necessarily result in rejection, since the peripheral wall is sufficiently thin to conform to the barrier piston.

Accordingly, the present invention pro vides a self-contained sealed pressurized barrier container sealed at the bottom and having a dis charge valve at the top and a piston in the con tainer serving as a gas-tight sealing barrier defining two chambers, one chamber communi cating with the valve and containing a product for discharge at the pressure of a propellant within the other chamber, the container being of insufficient strength to withstand an internal pressure greater than 120 psig, the peripheral wall of the container being sufficiently thin and deformable that the piston and the peripheral wall conform to each other and maintain a gastight seal as the piston moves through the container under the pressure of the propellant, the valve being constructed to afford, an opening, an effective flow through cross-sectional area allowing a useful rate of discharge of at least 0.8 per second at the pressure of the propellant and maintaining an effective flow rate at the reduced pressures following incremental discharges from the container.

In another aspect the invention provides a container body suitable for use in the manufacture of a valved self-contained sealed pressurized container, the container body being open at the top for receiving the product to be discharged and for receiving also a control valve for manually regulating the discharge of the product, the container body having a bottom wall provided with a port for receiving a propellant under pressure, the container body being of such strength that it cannot withstand an internal pressure greater than 120 psig, the body having therein a slidable barrier piston to serve as a separator between a product to be introduced through the open top and a propellant to be introduced through the port in the bottom wall, the peripheral wall of the container being sufficiently thin and deformable that the piston and the peripheral wall will conform to each other and maintain a gastight seal as the piston moves through the container under the pressure of the propellant.

The invention also provides a method of filling a container which is to be charged with a quantity of a product to be dispensed therefrom, and with a propellant, comprising providing a container body as defined above, charging the product through the open end into the space above the barrier piston, sealing a valve assembly to the upper edge of the container, charging through the port in the bottom wall into the space below the barrier piston either a gaseous propellant until a pressure of 6 to 40 psig at 700F is reached or a liquid propellant until a pressure of 6 to 24 psig at 70 F is reached or a gaseous and a liquid propellant until a pressure in the range of 6 to 24 psig at 700F is reached, and then sealing the charging port.

The invention will be described further, by way of example, with reference to the accompanying drawings.

In the accompanying drawings' Figure 1 is a central section, partly in elevation, of a low pressure barrier container constructed in accordance with the invention.

Figure 2 is an enlarged view, in central longitudinal section, of the tilt discharge valve in the closed condition.

Figure 3 shows the valve of Figure 2 in the open condition.

Figure 4 is a central section through a modi fied form of valve.

Figure 5 is a central section through a further modification.

Figure 6 is a view similar to Figure 1 of a modified container constructed with an integral bottom.

Referring to Figure 1, the container is indicated at 10 and is provided with a cylindrical wall 10a. It houses a barrier in the form of a piston 11 having a depending skirt 12. The bottom 13 of the container is sealed to the body or wall of the container by double seaming, as indicated at 14.

The product space 10b of the container is filled with the product through the open cylinder at the top thereof and prior to the installation of the valve 15. After the valve structure has been sealed to the top of the container (the valve being in the closed condition), the space 1 0c below the piston 11 and within the skirt 12 is charged with a quantity of propellant at a pressure of 6 to 40 psig through a port 16 which is thereafter closed by a plug 17 of rubber or the like.

In accordance with the invention, and by virtue of the reduced internal pressure, the cylinder or shell of the container, and also the bottom wall thereof, are made considerably thinner, and thus of lower weight, than such parts have heretofore been made for pressurised containers, whether of metal, plastic, paperboard or the like. Thus the cylindrical body 10 may be made of aluminum, as in beer and soft-drink cans, with a wall thickness of approximately 0.015 inch thickness of a standard aerosol can. The recommended wall thickness is 0.0025 times the container diameter.

The tubular body 10 of the container can also be formed of extruded thermoplastic material with a wall thickness of 0.015 inch to 0.030 inch, or it may be made of cardboard with a liquid-impervious internal lining of plastics or metal foil, or having a resin-treated interior surface impervious to gases and liquids.

Thus the peripheral wall of the container is strong enough to contain internal pressure to a maximum of, say, 120 psig but thin and deformable enough so that the piston 11, during its movement through the container under the pressure of propellant in the space 10c, tends to restore the cylindrical shape of the peripheral wall if it has previously been deformed e.g. dented, the peripheral wall being so deformable that it is able to conform to the piston and maintain a gas-tight seal with the piston as it moves through the containers.

The wall may even be so thin and deformable that the pressure of the propellant itself is capable of straightening out dents in the wall.

With the container filled at reduced pressure as above described, there is employed a discharge valve capable of delivering the product at an acceptable rate both at the original pressure and even as the pressure falls on successive discharges.

Satisfactory valves for use in combination with the above-described containers and having the necessary high flow-through capacity within the limited confines of the valve cup, or equiva lent structure, are illustrated by way of example in Figures 2 to 5.

The valve body includes a metallic, prefer ably aluminum, frame or cup 19 which can be crimped to the top edge of the body 10a, as indicated at 20, or double-seamed at the top edge of the cylinder, as shown at 20a in Figure 6.

The container constructed as described above, being designed for use with low internal pressures, is of such strength that it could not withstand an internal pressure greater than 120 psig.

Referring particularly to Figure 2, the valve includes the body of resilient rubber 21 or the like, which is sealed to the stem 22 through which the product is discharged on opening of the valve. The body 21 includes a bowed portion 23 of annular cross-section whose upper edge abuts against the shoulder 24 formed on the stem 22, thereby providing a seal at such region, and also a point of compression when the stem is tilted. The portion 23 of the valve body is arched downwardly and is then turned inwardly, as shown at 25, to form a further seal with the bottom portion of the stem 22.

The body 21 has an extension in the horizontal direction to form an annular seat 26 whose function will be described hereinafter.

The bottom of the valve stem 22 is in the form of spaced posts 27 providing passageways or ports 28 there-between which lead into the interior of the valve stem. The bottom ends of these posts are rigidly secured to a circular valve disc or head 20. The disc is provided with an annular sealing rib or ring 30 which norm ally penetrates into the seat 26 to provide a seal between the interior 10b of the container and the interior of the stem 22. The sealing ring 30 is located between the centre of the valve head and its periphery. A raised edge 31 is provided with a number of notches 33 to facilitate flow of product above the ring 30 when the valve is opened, the edge 31 then functioning principally as the fulcrum and as a spacer.

It will be evident from Figure 3 that upon tilting of the stem 22 in any direction, the disc 29 will pivot about a fulcrum at its perimeter and particularly at the raised edge 31 at a consider- able distance from the longitudinal axis of the stem, so that (as is shown at 32 in Figure 3), a large opening is made available for the discharge of the product from the interior 10b and into the stem 22. Preferably the outside diameter of the valve head is substantially 3 to 5 times the internal diameter of the stem.

Upon the tilting of the stem 22, the portion of the body 23 of the valve located in the direc tion of tilt is compressed, so that upon release of the stem, the latter is returned to its normal vertical position. When this occurs, the valve head 29 is returned into its closed condition in which the sealing ridge 30 is pressed into the seat 26. In the open condition of valve head 29, the product flows into the passageway 32 through which it bypasses the seal 30, where part of such seal remains in engagement with the seat.

It will be evident that when the stem 22 is tilted, its bottom end posts 27 tilt the valve head 20 downwardly, so that the product is able to pass between the raised edge 31 and a bend 34 in the valve cup. The resilience of the vertical portion 23 of the valve body enables the valve head to return to the closed, sealing position when the stem is released.

The modification of Figure 4 facilitates the side discharge of the product. In this embodiment, the valve stem fits at its upper end into a sleeve 37 forming part of a laterally directed nozzle 35 which is provided with a downwardly extending hood 36 serving to shield the valve.

The sleeve 37 presents a shoulder 38 against which stem 22 abuts, an annular groove being provided in the portion 37 for receiving an o-ring 39 of rubber or the like, to seal the valve stem at such point. In other respects, parts corresponding to the valve parts shown in Figure 2 and 3 are similarly numbered, and function in the same way.

It will be noted that, as in Figures 2 and 3, the raised edge 31 of the disc abuts against a downwardly extending portion of the valve cup to prevent side movement of the valve head upon tilting of the stem.

As shown in Figure 4, by reason of the fact that the hinge of the disc 29 is disposed at a rather large distance from the central axis of the valve stem, a small degree of tilt of the stem results in quite a large opening of the valve about its raised edge, thereby affording the valve a large flow capacity.

An even larger path for the product is provided for a given angle of tilt in the modification of Figure 5, wherein the fulcruming ring on the periphery of the valve head extends considerably above the bottom surface of the seat, and in the tilting action of the head engages a portion of the valve cup beyond the periphery of the valve seat, thereby increasing the radii of tilt both of the sealing ring and of the fulcruming ring.

As shown in Figure 5, the parts corresponding to those shown in Figures 2, 3 and 4 are indicated by the same numerals but with the letter "a" attached.

The principal differences over the structures of Figures 2, 3 and 4 reside in the greater height of the fulcruming ring 3 la than the sealing ring 30a, the top of the ring 3 la being also considerably higher than the bottom surface of the valv valve seat 26a, and in the greater radius of tilt of the valve head.

As in the other figures, the sealing ring 30a spaces the top surface of the valve head 29a from the bottom surface of the valve seat 26a which allows the ports 28a to extend for a con siderable distance below the bottom of the valve seat.

The fulcrum ring 3 la extends to a shoulder 19b of the valve cup, it being immaterial whether the ring exercises a sealing function against the valve cup or not. However, the shoulder 19b serves to center the valve head and prevents lateral displacement thereof on tilting of the valve stem 22a.

Upon tilting of the stem 22a in any direction the ring 3 lea will fulcrum against the shoulder 1 9b and will effect a relatively large opening movement in the region of the diagonally opposite point of the ring 3 la from its fulcrum by reason of the larger diameter of the valve head than its seat and the location of the fulcrum above the seat; so much so, that all of the sealing ring 30a is quickly separated from the valve seat on tilting of the stem 22a, and the product has access to all the ports 28a throughout the full 360 , with resultant low resistance to flow through the valve.

As in the other embodiments, the spacing of the top surface of the valve head from the bottom surface of the valve seat enables larger ports 28a to be easily provided at the bottom of the stem, i.e., they can be of increased height and hence afford increased flow cross-sectional area.

Figure 4 shows a pressurized container in which the bottom wall is not in the form of a separate member, crimped or double-seamed to the bottom edge of the container sidewall or shell, but is constructed in the manner of a beer can in which the bottom is integral with the side wall of the container. However, the bottom 1 la is provided with a charging port 16 as in Figure 1, for charging the propellant under pressure, after which the port is sealed with the usual plug 17.

The valves above described have a much greater rate of discharge of viscous materials of 10,000 cps and above at the reduced pressures than the known Clayton valve operating with a container charged at the same reduced pressure with the same materials. Thus, a Clayton valve employed with a pressurized container partly filled with a cheese preparation having a viscosity of about 300,000 cps, the valve having 3 openings at the bottom of the stem, each of about 0.09 inch in diameter delivered at 20 psig a flow rate of only 0.2 g. per second, which is not acceptable for cheese.

The valves described herein and likewise provided with 3 ports at the same location in the vertical stem as in the Clayton valve, yielded a flow rate for the same cheese preparation of 0.8 g. per second at 20 psig, which is an acceptable rate.

The considerably lower cost of pressurized valved packages of the invention has been stated hereinabove.

Specifically, in the case of tooth paste tubes, which at present are non-pressure packages, the largest practical size is 8 oz. and costs 10-11 cents (for the collapsible tube). In the quantities used by tooth paste manufacturers, my improved pressure pack can be sold at about the same price. Larger economy size tooth paste tubes are nor marketed because they are too cumbersome to handle. A low pressure barrier pack which will hold 12 oz. of tooth paste can be more easily handled and will cost 13-14 cents, which is about 1.125 cents/oz. This means that 12 oz. of tooth paste can be sold (including paste) for substantially less per oz. than collap sible 8 oz. tubes.

Similarly, significant economies will be obtained in the pressurized packaging of other fluent materials of viscosities of 10,000 cps and above, such as cheese, spreads, greases, lubri cants, hair pomades, and the like. In general, charging pressures of 10 to 15 psig will be ade quate to yield satisfactory rates of discharge for the viscous materials provided that a high capacity discharge valve, such as above described, is employed.

The economic advantage ofplastic containers with a 0.02 inch wall (as permitted by the pre sent invention), as compared to the known 0.06 inch wall, is illustrated by the following: Polyesters and acetals sell for about 80 cents/lb., and a 2 fluid oz. plastic container weights about 1 oz. for a 0.06 inch wall and 0.33 oz. for the 0.02 inch wall which is ade quate in accordance with the invention, a saving of 0.67 oz. for 3.3 cents/unit.

Examples of plastics and their tensile strengh strengths, as well as the wall thicknesses which will insure against bursting in containers having an outside diameter of 2 inches at different pressures are listed in the following table: Plastics Type Tensile Wall Thickness for 2" O.D. Cans in inches 120 Strength psi For 30 psi For 100% For 200% Safety Factor Safety Factor

Polyethylene Polypropylene Acrylonitrile- 2,500 .012 .024 .036 125 Butadiene Styrene Polyesters J 5,000 .006 .012 .018 130 Acrylics

Nylon Polyesters Polycarbonates > 10,000 .003 .006 .009 Acetals Reinforced Plastics Wall thickness for 1 O.D. cans are half of the above and for other O.D.'s in proportion.

The table indicates minimum thicknesses and shows only relative strengths, and not necessarily the thicknesses that will be used practically.

There is considerable overlap of plastics strengths and the above is only a guide.

Currently available plastics barrier containers have wall thicknesses in the range of about 0.100 or more for the lower strength plastics materials and about 0.060 for the strongest ones. Some of the wall thicknesses in the above table are too thin for practical use, but they can be increased to within a practical range while still remaining below 0.100 inch and 0.060 inch.

The following propellants in various admixtures can be employed in my improved pressurized packages, the proportion of liquid propellants being limited in the amounts and for the reasons set forth hereinabove.

EXAMPLES OF PROPELLANTS Pressure range 6-30 psig. Propellants and gases and mix tures of gases and propellants, but not limited to the following: I. For the 30 psig. range: 40% propellant 12, 60% propellant 11 25% propellant 12, 75% propellant 114 20% propellant 115, 80% propellant 114 Mixtures of propellants 22 with 113 and or 114 and/or 21 Propellant 318.

Hydrocarbon blends such as Butanes and Propanes with low pressure hydro carbons such as Pentanes, i.e., both the normal hydrocarbons and their isomers.

Air, nitrogen, carbon dioxide, any other inert gas at 30 psig.

II. For the 6 psig range: 12% propellant 12, 92% propellant 11 20% propellant 12, 80% propellant 113 90% propellant 114, 10% propellant 113 Propellant 21 Hydrocarbon blends of Pentanes with high pressure hydrocarbons such as Butanes and Propanes, i.e. both normal hydrocarbons and their isomers.

Air, nitrogen, carbon dioxide, any other inert gas at 6 psig.

For intermediate pressure ranges, different percentage mixtures of the above propellants will be used.

The above-named propellants and the proportions of mixtures of propellants for obtaining the specified pressures were taken from the well-known DuPont chart, from which the proportions for a 40 psig charging pressure, as well as for intermediate pressures between 6 and 40 psig. can be readily obtained.

Propellant 11 is Trichloromonofluoromethan 12 is Dichlorodifluoromethane 21 is Dichloromonofluoromethane 22 is Chlorodifluoromethane 114 is Dichiorotetrafluoroethane 318 is Octafluorocyclobutane 115 is Chloropentafluoroethane 113 is Trichlorotrifluoroethane The use of propellants other than air, nitrogen, or carbon dioxide is minimized in the described system, and where used will be used in smaller quantities.

As indicated above, the propellant can be either a gas at a charging pressure of 6 to 40 psig, or a volatile liquid at a charging pressure of 6 to 24 psig, or a mixture of a gas at the justmentioned pressure with a liquid propellant, the liquid in any case being in the limited amount which will all be evaporated to the vapour state before the temperature reaches 1300F.

In the filling of the container, there is provided the cylindrical shell which is open at the top and has a bottom wall which is either integral with the shell or is secured thereto in gastight manner. The bottom wall contains a charging port while the shell is provided with the barrier piston, preferably in the form of a hollow piston open at its bottom and occupying about one-third of the container interior. The product to be dispensed is then introduced through the open upper end, and the valve assembly is secured to the shell in leak-proof manner. The propellant is now charged into the piston through the port in the bottom wall, after which the port is plugged or otherwise sealed.

WHAT I CLAIM IS: 1. A self-contained sealed pressurized barrier container sealed at the bottom and having a discharge valve at the top and a piston in the container serving as a gas-tight sealing barrier defining two chambers, one chamber communicating with the valve and containing a product for discharge at the pressure of a propellant within the other chamber, the container being of insufficient strength to withstand an internal pressure greater than 120 psig, the peripheral wall of the container being sufficiently thin and deformable that the piston and the peripheral wall conform to each other and maintain a gastight seal as the piston moves through the container under the pressure of the propellant, the

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **.

Nylon Polyesters Polycarbonates > 10,000 .003 .006 .009 Acetals Reinforced Plastics Wall thickness for 1 O.D. cans are half of the above and for other O.D.'s in proportion.

The table indicates minimum thicknesses and shows only relative strengths, and not necessarily the thicknesses that will be used practically.

There is considerable overlap of plastics strengths and the above is only a guide.

Currently available plastics barrier containers have wall thicknesses in the range of about 0.100 or more for the lower strength plastics materials and about 0.060 for the strongest ones. Some of the wall thicknesses in the above table are too thin for practical use, but they can be increased to within a practical range while still remaining below 0.100 inch and 0.060 inch.

The following propellants in various admixtures can be employed in my improved pressurized packages, the proportion of liquid propellants being limited in the amounts and for the reasons set forth hereinabove.

EXAMPLES OF PROPELLANTS Pressure range 6-30 psig. Propellants and gases and mix tures of gases and propellants, but not limited to the following: I. For the 30 psig. range: 40% propellant 12, 60% propellant 11 25% propellant 12, 75% propellant 114 20% propellant 115, 80% propellant 114 Mixtures of propellants 22 with 113 and or 114 and/or 21 Propellant 318.

Hydrocarbon blends such as Butanes and Propanes with low pressure hydro carbons such as Pentanes, i.e., both the normal hydrocarbons and their isomers.

Air, nitrogen, carbon dioxide, any other inert gas at 30 psig.

II. For the 6 psig range: 12% propellant 12, 92% propellant 11 20% propellant 12, 80% propellant 113 90% propellant 114, 10% propellant 113 Propellant 21 Hydrocarbon blends of Pentanes with high pressure hydrocarbons such as Butanes and Propanes, i.e. both normal hydrocarbons and their isomers.

Air, nitrogen, carbon dioxide, any other inert gas at 6 psig.

For intermediate pressure ranges, different percentage mixtures of the above propellants will be used.

The above-named propellants and the proportions of mixtures of propellants for obtaining the specified pressures were taken from the well-known DuPont chart, from which the proportions for a 40 psig charging pressure, as well as for intermediate pressures between 6 and 40 psig. can be readily obtained.

Propellant 11 is Trichloromonofluoromethan

12 is Dichlorodifluoromethane

21 is Dichloromonofluoromethane

22 is Chlorodifluoromethane

114 is Dichiorotetrafluoroethane

318 is Octafluorocyclobutane

115 is Chloropentafluoroethane

113 is Trichlorotrifluoroethane The use of propellants other than air, nitrogen, or carbon dioxide is minimized in the described system, and where used will be used in smaller quantities.

As indicated above, the propellant can be either a gas at a charging pressure of 6 to 40 psig, or a volatile liquid at a charging pressure of 6 to 24 psig, or a mixture of a gas at the justmentioned pressure with a liquid propellant, the liquid in any case being in the limited amount which will all be evaporated to the vapour state before the temperature reaches 1300F.

In the filling of the container, there is provided the cylindrical shell which is open at the top and has a bottom wall which is either integral with the shell or is secured thereto in gastight manner. The bottom wall contains a charging port while the shell is provided with the barrier piston, preferably in the form of a hollow piston open at its bottom and occupying about one-third of the container interior. The product to be dispensed is then introduced through the open upper end, and the valve assembly is secured to the shell in leak-proof manner. The propellant is now charged into the piston through the port in the bottom wall, after which the port is plugged or otherwise sealed.

WHAT I CLAIM IS: 1. A self-contained sealed pressurized barrier container sealed at the bottom and having a discharge valve at the top and a piston in the container serving as a gas-tight sealing barrier defining two chambers, one chamber communicating with the valve and containing a product for discharge at the pressure of a propellant within the other chamber, the container being of insufficient strength to withstand an internal pressure greater than 120 psig, the peripheral wall of the container being sufficiently thin and deformable that the piston and the peripheral wall conform to each other and maintain a gastight seal as the piston moves through the container under the pressure of the propellant, the

valve being constructed to afford, on opening, an effective flow-through cross-sectional area allowing a useful rate of discharge of at least 0.8 g per second at the pressure of the propellant and maintaining an effective flow rate at the reduced pressures following incremental discharges from the container.
2. A container as claimed in Claim 1, wherein the peripheral wall is of such thinness and deformability that the internal pressure is capable of straightening out dents in the wall.
3. A container as claimed in Claim 1, wherein the peripheral wall is made of aluminum, and wherein the thickness of the peripheral wall in inches is substantially equal to the product of the container diameter in inches multiplies by 0.0025.
4. A container as claimed in Claim 1, wherein the peripheral wall is made of aluminum, and wherein the thickness of the peripheral wall is 0.005 inch.
5. A container as claimed in Claim 1, wherein the peripheral wall is made of cardboard which is lined interiorly with a liquid-impervious foil.
6. A container as claimed in Claim 1, wherein the peripheral wall is composed of plastics material.
7. A container as claimed in Claim 6, wherein the wall thickness is less than 0.060 inch.
8. A container as claimed in Claim 1, wherein the valve includes a hollow valve stem having a plurality of ports therein for receiving the discharging product on opening of the valve, a valve head secured to the bottom of the stem to be actuated on tilting of the stem, an annular valve seat through which the stem passes, and a sealing ring projecting above the top surface of the head and engaging the bottom surface of the seat to seal the stem against access by the product when the valve is closed, the sealing ring acting also to space the valve head from the valve seat in the closed condition of the valve and enabling the stem to extend below the bottom surface of the valve seat, the ports in the stem extending below the bottom of the valve seat so that all ports are accessible to the flow of product over the sealing ring on opening of the valve.
9. A container as claimed in Claim 8, wherein the sealing ring is located between the centre of the valve head and the periphery of the valve head.
10. A container as claimed in Claim 1, with a valve cup having a downwardly extending wall wherein the valve is provided with a hollow discharge stem having a plurality of ports about its bottom end for the entry of the product under pressure, the valve having an annular seat and a head secured to the stem, the head being of larger diameter than the seat, and extending substantially to the valve cup wall, so that on tilting of the stem, the head tilts about a fulcrum against the wall and beyond the periphery of the seat and affords a passageway for the product for a full 360" about the ports.
11. A container as claimed in Claim 1, wherein the valve includes a valve seat, an abutment above the bottom surface of the seat and beyond the periphery of the seat, a tiltable hollow valve stem provided with entry ports for the discharge of the product, and a valve head secured to the stem and tiltable therewith, the valve head engaging the valve seat in the closed condition of the valve and being of larger diameter than the seat and having a raised peripheral edge extending above the level of the bottom of the valve seat and engaging the said abutment on opening of the valve to tilt about a fulcrum thereagainst, whereupon the valve head is removed completely from engagement with the valve seat.
12. A container as claimed in Claim 1, wherein the valve includes a valve seat, a hollow stem for the discharge of the product, and a valve head secured to the stem and tiltable therewith, the valve head tilting about a fulcrum at a portion of its periphery, and the outside diameter of the valve head being substantially 3 to 5 times the internal diameter of the stem.
13. A container as claimed in Claim 1, wherein the valve comprises a body providing an annular seat, a hollow valve stem passing through the valve seat and through which the product is discharged under pressure, a valve head bearing against the seat to cut off flow of product into the valve stem, the valve stem having one or more entry ports and being connected to the valve head, the stem being operable to move the head away from its seat to provide a passageway for the product to the port or ports of the stem, and an annular sealing ring projecting above the top surface of the head and, in the closed condition of the valve, bearing against the bottom of the seat under the pressure of the product against the bottom surface of the head to effect sealing of the said passageway.
14. A container as claimed in Claim 13, wherein the valve stem is tilt able and wherein the valve head, on tilting of the stem, is tilted about a fulcrum at its periphery, to afford a wedge-shaped passageway for the product, the said passageway being then at a maximum height at a point diametrically opposite the fulcrum and diminishing toward the fulcrum.
15. A container as claimed in Claim 13, wherein the top surface of the valve head is spaced from the bottom surface of the valve seat, in the closed condition, and wherein the stem extends below the bottom surface of the seat, the entry ports extending substantially to the top surface of the head and below the level of the bottom of the seat.
16. A container as claimed in Claim 12, including means for barring the valve head again against lateral displacement.
17. A container as claimed in Claim 13, wherein the valve body is shaped to provide an annular chamber extending substantially to the tops of the ports in the stem and encompassing them, whereby upon opening of the valve, the product whose flow is controlled by the valve has access to all the ports by way of such chamber.
18. A container as claimed in Claim 1, wherein the propellant comprises a liquefied gas in such limited amount that it is all evaporated before the temperature reaches 1300F.
19. A container as claimed in Claim 1, wherein the charging pressure of the propellant is 10 to 15 psig.
20. A container as claimed in Claim 1, wherein the pressure within the container is 20 psig and the product is of approximately 300,000 cps viscosity, the valve being of such large flow-through capacity that, upon opening of the valve, the product is discharged substan tially at the rate of 0.8 g per second.
21. A container as claimed in Claim 1, in which the product has a viscosity of at least 10,000 cps at 70"F.
22. A container body suitable for use in the manufacture of a valved self-contained sealed pressurized container, the container body being open at the top for receiving the product to be discharged and for receiving also a control valve for manually regulating the discharge of the product, the container body having a bottom wall provided with a port for receiving a propellant under pressure, the container body being of such strength that it cannot withstand an internal pressure greater than 120 psig, the body having therein a slidable barrier piston to serve as a separator between a product to be introduced through the open top and a propellant to be introduced through the port in the bottom wall, the peripheral wall of the container being sufficiently thin and deformable that the piston and the peripheral wall will conform to each other and maintain a gas-tight seal as the piston moves through the container under the pressure of the propellant.
23. A container body as claimed in Claim 22, wherein the peripheral wall is made of aluminum, and wherein the thickness of the peripheral wall in inches is approximately equal to the product of the container body diameter in inches multiplied by 0.0025.
24. A container body as claimed in Claim 22, wherein the peripheral wall is made of aluminum, and wherein the thickness of the pen.

pheral wall is approximately 0.005 inch.
25. A container body as claimed in Claim 22, wherein the peripheral wall is made of cardboard provided with a liquid-impervious surface interiorly thereof.
26. A method of filling a self-contained sealed pressurized container which is to be charged with a quantity of a product to be dispensed therefrom, and with a propellant, comprising providing a container body according to claim 22, charging the product through the open top into the space above the barrier piston piston, sealing a valve assembly to the upper edge of the container, charging through the port in the bottom wall into the space below the barrier piston a gaseous propellant until a pressure in the range of 6 to 40 psig at 700F is reached or a liquid propellant until a pressure in the range of 6 to 24 psig at 70"F is reached or a gaseous and a liquid propellant until a pressure in the range of 6 to 24 psig at 70 F is reached, and then sealing the charging port.
27. A method as claimed in Claim 26, wherein the propellant is one that attains a maximum pressure of only about 90 psig at 1300F.
28. A method as claimed in Claim 26, wherein the propellant comprises liquified gas in such limited proportion that it is completely evaporated below 130"F.
29. A pressurized container substantially as described herein with reference to, and as shown in, the accompanying drawings.
30. A method of filling a container, substantially as described herein with reference to the accompanying drawings.