US3372839A - Dispenser with means to prevent bursting of the container - Google Patents

Description

March 12, 1968 J. A. HAY DISPENSER WITH MEANS T0 3,372,839 ENT BURSTING 6 OF THE couwmm Filed Oct. 31, 19

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INVENTORQ JOHN A. HAYES BY 9}? WWIAGENT United States Patent 3,372,839 DISPENSER WITH MEANS TO PREVENT BURSTING OF THE CONTAINER John A. Hayes, Philadelphia, Pa., assignor to E. I. du Pont de Nemours and Company, Wilmington, Del., a corporation of Delaware Filed Oct. 31, 1966, Ser. No. 590,572

2 Claims. (Cl. 22294) ABSTRACT OF THE DISCLOSURE An aerosol dispenser is provided which is substantially free of exposion hazards and which has one or more storage chambers; this dispenser has a ruptu-rable wall in the valve head at the bottom of the valve stem passage adapted to rupture and prevent the container from bursting if the dispenser is inadvertently subjected to conditions which cause an undue rise of pressure within the container.

This invention rel-ates to pressurized dispensers including those commonly known as aerosol dispensers. A prefer-red embodiment of the invention relates to a dispenser adapted for storing at least two dilferent fluid materials in isolation from each other and for the intermittent dispensing of these materials in con-tact with each other.

A well known and widely used type of aerosol dispenser is described in US. Patent 3,132,774, issued May 12, 1964, to J. W. Soifer; this dispenser employs a tiltopening valve and it is adapted for dispensing whipped cream and other products under the pressure of a gas Within the dispensing container. Another useful aerosol dispenser is described in my copending US. patent application Ser. No. 520,787, filed Jan. 14, 1966, now Patent No. 3,326,416 of June 20, 1967; this dispenser, which is adapted for dispensing warm shaving lather and other products through a special kind of tilt-opening valve, is capable of storing at least two different liquid materials in isolation from each other, including materials which are very reactive with each other, prior to the codispensing of said materials through said valve.

Although such pressurized dispensers are very useful, they are not entirely satisfactory from the standpoint of safety. A dangerous explosion can occur when the pressure within the dispenser becomes high enough to burst the container, for example by exposure of the dispenser to undue heat, or by pressure-generating chemical reaction of one or more m-taerials within the closed dispenser. The dispenser provided by the present invention is substantially free of such explosion hazards.

The invention is illustrated in the four figures of the attached drawing.

FIGURE 1 shows an embodiment of the novel dispenser in central vertical section and partially broken away; a portion of .the .valve stem is shown in front View. The dispensing valve is in the closed postiion (erect or nontilted) and the rupturable wall can be seen at the bottom of the valve head.

FIGURE 2 shows a portion of the dispenser of FIG- URE 1 in which the dispensing valve is in the open (tilted) position.

FIGURE 3 shows an enlarged perspective view of the assembly of the valve stem, valve head and rupturable wall shown in FIGURE 1.

FIGURE 4 shows a portion of the dispenser of FIG- URE 1 in which the rupturable wall at the bottom of the valve head has been ruptured by excessive pressure within the dispenser which pressure might otherwise have caused the outer container to burst.

In FIGURE 1, outer container 34, which is adapted for storing a fluid under pressure, is a can of the type 3,372,839 Patented Mar. 12, 1968 commonly used in aerosol foam dispensers. The upper portion of can 34 is rounded and tapered to form a circular opening surrounded by a rolled bead 18 spun from the metal of the can. The rolled edge of bowl-shaped cover 19 tightly engages bead 18, and after the contents of the can are inserted, it is crimped therewith to form a pressure-proof seal. Top wall 20 of can 34 has an aperture which is outwardly flanged about axis a perpendicular to wall 20; in this aperture is lockingly and sealingly fitted a tilt-opening self-closing dispensing valve. The dispensing valve comprises a tubular seal 17 made of a resilient elastic rubber composition fitted sealingly in aperture 27; the valve also comprises a tubular stem 14 made of a relatively rigid plastic composition fitted co-axially (on axis a) and sealingly in seal 17. The rigid stem has relatively little elastic deformation under load compared with that of resilient seal 17. Stem 14 terminates inside of can 34 in disc-shaped valve head 25 and terminates outside of can 34 in dispenser outlet 10. By gently pressing the side of stem 14 near the outlet, the stem can be tilted about a pivot point located between its two ends (near the bottom of ring 15); as the stem is tilted, its lower portion moves laterally within annular gap 30. When the tilting pressure is removed from the valve stem, the stem is returned to the erect, closed position by the resilient elastic rubber seal.

The exterior portion (above aperture 27) of stem 14 has (a) a laterally extending shoulder 16 which abuts against the upper end face 13 of seal 17 at a level remote from that of wall 20 and (b) a laterally extending ring 15 in locking contact with a matching groove in the inner wall of seal 17.

Collapsible inner container 33 is a flexible plastic tube which is smaller than can 34 and has a beaded upper end 23 sealingly fitted in annular groove 31 in the side Wall of valve head 25. Thus, there is a chamber outside of tube 33 and within can 34 in which fluid 38 can be stored in isolation from the fluid in the tube. Lower face 32 of valve head 25 forms the top wall of collapsible container 33; the lower face of rup-turable wall 40 forms part of the lower face of the valve head. In a sense, end face 21 also forms part of the top wall of container 33 since it serves as a closure for channels 24 when the valve is closed. The heat-sealed lower end 35 of tube 33 almost touches bottom wall 36 of can 34.

Tubular seal 17 has an enlarged lower portion 28 which has a large washer-like sealing surface in contact with the inner side of wall 20 adjacent aperture 27, and which terminates inside of can 34 in an annular end face 21 at a level remote from the level of top wall 20, and valve head 25 has a laterally extending annular shoulder 22 in sealing contact with end face 21, thereby forming a breachable seal. When the valve is closed, the resilient material of seal 17 is slightly compressed at end face 21. The inside diameter (inner wall) of the lower portion 28 of tubular seal 17 in the region adjacent end face 21 is enlarged so that this portion of the seal is separated from the lower portion of stem 14 by an annular gap or chamber 20 (counterbore recess) which is in communication with dispenser outlet 10 through lateral port 29 and central passage 26 of stem 14. Port 29 is provided by drilling a hole diametrically through the valve stem just above shoulder 22. Annular chamber 30 is partitioned by the breachable seal from the chamber containing liquid 38, the lower portion 26a of central passage 26 is partitioned by rupturable wall 40 from the interior of tube 33.

Rupturable wall 40 is made of a material which is substantially impervious to the fluid within tube 33; the strength of wall 40 is such that it will withstand normal pressures within the dispenser, and it will rupture at a predetermined pressure below that which would burst can 34. As shown in FIGURE 4, after rupturable wall 40 has burst due to an excessive build-up of pressure within the dispenser, there is communication between the inside of the dispenser and the dispenser outlet by way of portion 26a of the central passage of stem 14. Thus, rupturable wall 40 is adapted to prevent the bursting of can 34.

As shown in FIGURE 3, valve head is perforated with eight channels 24. In this embodiment of the invention, the channels were drilled with a No. 73 drill so that the channels are equidistant from each other and from the center point of the valve head. These channels provide communication between the interior of collapsible tube 33 and (a) end face 21 of tubular seal 17 when the valve is closed and (b) gap when the valve is open.

It can be seen in FIGURE 2 that the interior of the chamber containing fluid 38 and the interior of tube 33 are in communication with annular chamber 30 (and therefore port 29, passage 26 and outlet 10) only when stem 14 is tilted enough to breach the seal and thereby provide a gap 37 between end face 21 of the seal and annular shoulder 22 of the valve head.

Cap 11 has internal threads to match external threads 12 of the upper portion of stem 14. When the cap is in place, its lower edge abuts upon head 18; thus stem 14 is locked in the erect position. Hole 41 at the top of cap 11 can be filled if desired with a plug (not shown) which will readily be removed at a pressure below the pressure required to rupture the rupturable wall 40.

The dispenser shown in FIGURE 1 is adapted for storing fluid 38 (including a propellant) in can 34 and a ditferent fluid 39 in tube 33, and for dispensing these two fluids simultaneously and intermittently through outlet 10. When using the dispenser, cap 11 is removed and the dispenser is inverted so that the upper portion of can 34 is filled with fluid, stem 14 is tilted to open the valve, and fluids 38 and 39 become mixed as they flow into gap 30 through gap 37 en route to outlet 10. The flow of both fluids into gap 30 stops the instant the valve stem is permitted to return to the erect position and starts again the instant the valve stem is tilted.

Various modifications of the dispenser described above which will be obvious to one skilled in the art in View of the present disclosure can be made without departing from the spirit of the present invention. For example, with reference to FIGURE 1, cap 11 and the threaded portion of stem 14 can be omitted. Stem 14' can be made of any suitable rigid material (e.g., plastic, metal or glass) having sufficient strength and resistance to the liquids being dispensed. Valve stem 14, valve head 25 and rupturable wall 40 can be molded as a composite single piece from polyethylene or other suitable plastic. Or an assembly consisting of stem 14 and head 25 can have wall 40 attached thereto by known heat-sealing, cementing or mechanical fastening means so as to form a rupturable partition between passage 26 and the area beneath the valve head.

Part of the upper portion of tubular seal 17 can be replaced with a helical spring whose upper end abuts against annular shoulder 16 and whose lower end abuts against the upper end face of seal 17, the latter being in a horizontal plane between that of ring 15 and top wall 20. Seal 17 can be made of any suitable resilient material (e. g., natural or synthetic rubber or polyethylene) having the required resilience and resistance to the liquids being dispensed.

Collapsible tube 33 can be made of any suitable flexible or collapsible material having the required resistance to the fiuids 38 and 39, for example, plastic, rubber or metal. Various known fastening methods can of course be employed for attaching tube 33 to the valve head so that the interior of the tube communicates with channels 24.

Channels 24 through valve head 25 can be varied in size and number to provide the desired discharge of fluid from tube 33. For example, one portion of the valve head can contain more channels or larger channels than another portion, and an indicator can be provided on top of the dispenser to show which direction to tilt the valve stem to dispense a mixture containing a greater proportion of fluid 39 for one purpose than for another.

End face 21 (in the non-compressed state) can have a slope of about 20 from the horizontal as measured radially in an outward and upward direction from axis a, this feature, which is not a novel feature of the present invention, tends to facilitate the sliding and rocking movement of the valve head relative to the end face when the valve is opened and closed.

A source of fluid pressure is provided by any suitable known means for moving the fluids through gap 37 and outlet 10 when the valve is open. For example, a volatile organic material or a compressed gas referred to in the art as propellant" can be introduced into can 34, thereby pressurizing both the can and the colapsible tube 33. The useful propellants include those known to be operable in an aerosol-type package, for example, a compressed gas (e.g., nitrous oxide or carbon dioxide), isobutane, straight-chain saturated aliphatic hydrocarbons, and water-insoluble chlorine and fluorine substituted hydrocarbons having a vapor pressure of about 15-85 p.s.i.g. at 21 C. About 325% of propellant is usually required based on the combined weight of propellant and other fluid in can 34, however, a substantially greater amount of propellant is used for some applications. The dispenser is preferably shaken briefly to obtain a collodial dispersion of the propellant in fluid 38 just before opening the valve.

Dispensers constructed according to the present invention have important advantages from the standpoint of safety since they are substantially free of explosion hazards. These novel dispensers are useful for dispensing many diiferent kinds of fluid materials including, for example, warm shaving lather, adhesive compositions, paint compositions, insecticides, cleaning and bleaching compositions, caulking compositions, heated liniment, whipped cream, polyurethane foam, and multi-colored cosmetic creams, food products and tooth paste.

Any dangerous build-up of pressure within the dispenser of the present invention is avoided by the rupture of the rupturable wall at the bottom of the central passage of the tubular valve stem with resultant release of pressure through the dispenser outlet before the pressure becomes great enough to cause the dispenser can to burst.

The examples which follow are given for the purpose of illustrating the invention. All quantities shown are on aweight basis unless otherwise indicated.

EXAMPLE 1 The preparation and use of the novel apparatus for the instantaneous preparation and dispensing of warm shaving lather is illustrated as follows.

An aqueous foamable composition is prepared according to the following formula.

Formula A Parts Stearic acid, triple pressed 6.3- Coconut oil fatty acid 2.7 Triethanolamine 4.6 Sorbitol, 70% aqueous solution 10.0 Water 76.4

In preparing Formula A, the first two ingredients are mixed together at C. In a separate container, the water is heated to C. and the third and fourth ingredients are added thereto with stirring. The latter mixture, while still hot, is added gradually with stirring to the heated mixture of the first two ingredients. After heating the resulting Formula A composition for an additional 10 minutes at 95 C., it is cooled to 21C.

A Formula B mixture is prepared by mixing 8 parts of potassium sulfite with 92 parts of Formula A. V

The dispenser shown in FIGURE 1 is prepared for use by first filling can 34 about two-thirds full with the Formula B mixture described above. The can and its contents are placed in a refrigerator until chilled to 25 C.

The can is constructed to withstand an internal pressure of at least 270 p.s.i.g. Valve stem 14, valve head 25 and rupturable wall 40 are molded as a composite single piece of plastic from high density polyethylene. Rupturable Wall 40, which has a thickness of 4.5 mils, will rupture if and when the pressure within the dispenser reaches 225 p.s.i.g.; passage 26 has a diameter of inch at its bottom. I

Valve stem 14, tubular sea117 and cover 19 are assembled as described above and shown in FIGURE 1. Before this valve and cover assembly is attached to the can, collapsible tube'33 is filled with 7% hydrogen peroxide and attached to the lower end of the valve stem (valve head 25) so that the beaded top 23 of tube 33 is engaged with groove 31 of the valve head. If desired, the top 23 of the tube'can be heat-sealed to the valve head.

With the can audits contents at 25 C., chilled propellant (at a temperature of -25 C.) is introduced into the can in an amount equal to 8.5% of the combined weight of Formula B mixture and propellant. The propellant consists of a 40/60 mixture of dichlorodifluoro methane and symmetrical dichlorotetrafluoroethane.

Now the assembly described in the previous paragraph is placed in position }'with the cover fitted on the can, and the rolled edge of cover 19 is crimped with can bead 18 to form a pressure-proof seal. The dispenser cap is screwed on so that its lower end tightly abuts upon the top of cover 19. Cap 11 provides an obvious means to insure that the valve will not be inadvertently opened during storage and shipment ofthe dispenser.

The full dispenser is warmed to 21 C. The pressure within the dispenser is now 45 p.s.i.g. Just prior to use, the dispenser is shaken briefly so that the Formula B mixture and propellant in can 34 are adequately blended with one another. None of the liquid in either the can or the collapsible tube can escape into gap 30 during the shaking because of the sealing contact between end face 21 of the tubular seal and annular shoulder 22 of the valve head. Cap 11 is removed, then the dispenser is held in an inverted position (bottom side up), the valve is opened by tilting the valve stem, a quantity of warm creamy lather is dispensed from outlet 10, and the valve is allowed to close. The temperature of the dispensed lather is 48 C. The valve is rapidly and repeatedly opened and closed to dispense numerous small batches of warm lather.

When a person, applies the resulting warm lather to the hairy areas of the face and neck by means of his fingers or a brush, the lather comfortably and efliciently prepares these areas for shaving.

While the valve. is held open by tilting the valve stem, the separately stored liquid materials within can 34 and tube 33 flow through gap 37 into gap 30; and as the resulting foam-forming liquid mixture entering gap 30 flows through port 29, passage 26 and outlet 10, it becomes heated substantially instantaneously as the result of a rapid exothermic reaction between the potassium sulfite and the hydrogen peroxide.

A dispenser is prepared as described in Example 1 except the side wall of can 34 is provided with a gas inlet connected to a source of compressed nitrogen. After the full dispenser is warmed to 21 C., compressed nitrogen is introduced therein through the gas inlet and the pressure within the dispenser is gradually increased. When the pressure in the dispenser reaches 225 p.s.i.g., rupturable wall 40 ruptures and the pressure inside the dispenser at once drops to a very low level as a portion of the contents of the dispenser is discharged through passage 26 and outlet 10.

For purposes of comparison, a dispenser is prepared and tested in the manner described in the previous paragraph except valve head 25 has no rupturable wall, the

fragments in all directions.

EXAMPLE 2 A dispenser is prepared as described in Example 1 except the rupturable Wall of polyethylene is replaced with a piece of aluminum foil having a thickness of 1.2 mils and a diameter slightly larger than that of passage 26. The aluminum foil wall is sealingly fastened to the bottom of valve head 25 at the bottom of passage 26 by means of a heat-seal adhesive. When this dispenser is tested with compressed nitrogen in the manner described above, the rupturable wall of aluminum ruptures when the pressure inside the dispenser reaches 250 p.s.i.g. The excessive pressure is thereby harmlessly expelled through the dispenser outlet.

One skilled in the art, after reading the present disclosure, will have no difliculty in selecting a rupturable wall of suitable strength and chemical resistance for any desired application of the novel dispenser. And it will be obvious that the inner container 33 and valve head channels 24 can be eliminated in applications where there is no need to use separately stored fluid materials.

I claim:

1. In a dispenser comprising:

a container adapted for storing a fluid under superatmospheric pressure and having an aperture in which is sealingly fastened a dispensing valve,

said dispensing valve having a resilient tubular seal fitted sealingly in said aperture and a rigid tubular stem fitted coaxially and sealingly in said tubular seal, said stem terminating inside of the container in a valve head having a laterally extending annular shoulder, terminating outside of the container in a dispenser outlet, and being tiltable about an intermediate pivot point,

said tubular seal having a lower portion which (1) terminates inside of the container in an annular end face that forms a breachable seal with the laterally extending annular shoulder of the valve head, and (2) has an inner wall defining an annular chamber that surrounds said tubular stem, communicates with the dispenser outlet through a port in the stern wall, and is partitioned by said breachable seal from the interior of the container,

the interior of the container being in communication with said annular chamber and thereby with the dispenser outlet only when said tubular stem is tilted enough to breach the seal (and form a gap) between said end face and said annular shoulder,

the improvement wherein the central portion of said valve head has a rupturable wall of fluidimpervious material which (I) separates the interior of said container from the interior of said tubular stem, (II) is adapted to withstand normal pressures within the container, and (III) is adapted to rupture at a predetermined pressure below that which would burst the container and thereby provide communication between the inside of the container and the dispenser outlet sulficient to prevent bursting of the container.

2. In a dispenser, adapted for storing at least two different fluid materials in isolation from each other for dispensing said materials simultaneously and intermittently through a common outlet, comprising:

an outer container (A) adapted for storing a fluid under super-atmospheric pressure and having an aperture in which is sealingly fastened a dispensing valve,

said dispensing valve having a resilient tubular seal fitted sealingly in said aperture and a rigid tubular stem fitted coaxially and sealingly in said tubular seal, said stern terminating inside of container (A) in a valve head having a laterally extending annular '7 shoulder, terminating outside of container (A) in a dispenser outlet, and being tiltable about an intermediate pivot point, and collapsible inner container (B) within and smaller than container (A) and having its upper end sealingby said end face of the tubular seal in the area of contact with said annular shoulder,

the improvement wherein the central pottionof said a valve head has a rupturable Wall of fluid-impervious ly attached to said valve head, thereby providing a material which (I) separates the interior of container chamber (C) which is outside of (B) and within (B) from the interior of saidtubular stem, (II) is (A); adapted to withstand normal pressures within the said tubular seal having alower portion (1) terminating dispenser, and (III) is adapted to rupture at a preinside of container (A) in an annular end face which 10 determined pressure] below.- that which would burst forms a breachable seal with the laterally extending container (A) and thereby provide communication annular shoulder of the valve' head, and (2) having between the inside of the dispenser and the dispenser an inner wall defining an annular chamber which suroutlet sufiicient to prevent bursting of container (A). rounds said tubular stem, communicates with the dispenser outlet through a port in the stem wall, and 15 References Cited is partitioned by said breachable seal from the in- UNITED STATES PATENTS terior of chamber (C); Y said valve head being perforated with at least one 3/1963 Samuel ""7'T'"""" 222*396 channel which, when the valve is closed, communi- FOREIGN PATENTS cates with the interior container (B) and is sealed 20 5/ 1963 Great Britain.

ROBERT B. REEVES, Primary EicaminerJ t t f t B a d c amber C bein he m erlors 0 con amer n h g H. S. LANE, Assistant Examiner in communication with said annular chamber and

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