Container For The Storage And Delivery Of A Fluid Or Pasty Material

Abstract

A tube or like hollow cylindrical container for the storage and delivery of a fluid or pasty material has an insert fitted into one end. The insert comprises a piston axially movable along the tube, a bottom for the container, a bellows-type bag containing gas under pressure and acting between the container bottom and the back of the piston and spring hooks on the piston engageable with holes in the container bottom so that the piston is prevented from moving away from the container bottom, the hooks being releasable from the outside when material is to be delivered from the container. Various modifications of this constructions are described and illustrated.

Description

The invention relates to a tube or like hollow cylindrical container for the storage and delivery of a fluid or pasty material, having a piston which is longitudinally movable in the container to urge the material to the delivery aperture and which can be urged forwardly by a pressure medium contained in an insert fitted into the container.

A container of this type is shown in FIG. 1 of French Pat. Specification No. 1,046,624 in which the insert containing the drive gas or other pressure medium comprises a rigid-walled chamber at the bottom of the container and which is provided with a gas valve which opens to allow the generation below the driving piston of a gas pressure which tends to urge the piston towards the delivery aperture of the container. This container suffers on the one hand from the disadvantage that, although the gas valve is closed after use, there remains a gas pressure acting directly against the piston, whereby gases can pass between the container wall and the piston into the contents of the container and mix therewith so that such a container is not suited for the storage of foodstuffs such as whipped cream, cheese and the like. On the other hand, a container of this nature is an expensive construction as the gas valve represents a considerable part of the costs and also requires particular sealing.

The invention is based on the problem of designing a container of the type shown in the French specification in such a way that the disadvantages from which it suffers hitherto are eliminated, and in particular the contents and the drive gas are completely separated without the bottom of the container requiring a gastight seal.

In accordance with the invention, the driving piston is loadable on its side remote from the delivery aperture, by a preferably bellowslike foldable bag which is enclosed in the container and contains the pressure medium and which, together with the container bottom, forms the insert fitted into the container.

While, therefore, in the case of a container with a gas valve, pressure is only generated when required by opening the gas valve, and is then disadvantageously maintained, in the container according to the invention there is already a pressure before the container used, this pressure being stored in the expandable bag.

Storing the pressure gas in the bag insert means that there is no possibility of pressure gas and container contents being mixed. In FIG. 3 of French Pat. Specification No. 1,046,624, gas is made to flow from the rigid-walled chamber by way of the gas valve into a bag insert which, by expansion, then urges the container contents towards the delivery aperture directly, that is without the interposition of a piston. With this construction, however, it is not possible for the container to be completely emptied. In this case, too, a separate gas valve is required which increases the production costs of the container. Therefore, the container according to the invention can be produced more simply and cheaply particularly as, in addition to the omission of a gas valve, combining the parts forming the insert into a unit which can be prepared separately enables the container to be produced at an even more favorable cost, as these parts can be produced in a single workpiece, for example of plastics material.

In accordance with a preferred embodiment of the container according to the invention, the bag which contains the pressure medium can be secured to a part of the container, at least when the container is full, by an externally releasable lock means which is part of the insert and allows the pressure medium for advancing the piston to take effect only after it has been released. In the containers shown in the French specification, the manually operable gas valve allows the pressure medium to take effect to drive out the filling material only after the valve has been opened, but in this embodiment of the invention the expandable bag which contains the gas stored in a liquefied form is at first secured b the mechanical look means so that the pressure cannot act on the material before the container is used. The locking action on the pressure medium bag is only removed when the tubular container is to be used for the first time to deliver its contents, so that at least until that moment, the contents and, therefore, the container itself are not under the pressure of the drive gas. Only when the locking action has been released does the pressure of the gas in the bag insert act on the driving piston which transmits this pressure to the container contents and permits them to issue as required from the container through the delivery aperture.

Combining the bag insert and the container bottom with the lock means to form a unit which is separate from the container before filling, also provides however further advantages. On the one hand, this insert including the gas filling can be manufactured in a preproduction process. In this case, this insert is produced separately from the operation of filling the container with the particular material in question. This insert is also desirably supplied to the tube manufacturer separately from the containers; as in this case, owing to the locking action on the bag, the gas is stored in an extremely small space, such inserts are extraordinarily compact for delivery purposes, and require little packaging material. The manufacture of this separate insert also enjoys the advantage that it permits particularly rational filling and closing of the container as the entire open bottom surface area of the container is available for filling and the container can be sealed in a rational manner after the filling operation simply by applying a pressure, for example engaging the container bottom which forms one part of this insert, in a bead formed in the wall of the container at its free end. Obviously, however, it is also possible for the container to be supplied to the factory with the insert already fitted and including the gas charge, the factory when filling the container in this case by way of the delivery aperture of the container. At any event, the tubular container does not need to be airtight sealed as the drive gas is contained in the bag insert in an airtight manner. As the pressure force of the gas contained in the bag insert is in most cases only released by the consumer releasing the lock means, when the container to be used for the first time, it is practically impossible for the container to be unintentionally discharged during transportation and storage.

In accordance with a particularly advantageous form of this preferred embodiment of the container according to the invention, to provide the mechanical lock means for the bag, the driving piston forming the head thereof has extensions with, for example, hook-shaped ends which can be engaged into holes in the container bottom or in recesses provided in the lower wall region of the container. Therefore, in this embodiment, the driving piston is incorporated in the insert formed by the bag, container bottom and lock means, resulting generally in even great simplification of manufacture of the container. In addition, such a container offers considerable safety as regards the danger of accident the case of damage caused by excess pressure, as such excess pressure can escape through the holes provided for the lock means in the container bottom, or the recesses in the wall of the container, thus falling to such an extent that the container can be made with a relatively small wall thickness without thereby substantially endangering its operating reliability.

The same advantage is found when, in accordance with a further embodiment of the invention, for providing the mechanical lock means for the bag, the head of the bag or a plate carried thereby has extensions with, for example, spherical ends which can engage in wedge-shaped slots formed in the container bottom, while the piston which is produced separately from the bag, preferably comprises resilient material.

In both embodiments, the locking action on the bag insert is released insofar as the hook-shaped or spherical ends of the extensions of the driving piston or the bag or its head plate are disengaged so that for the first and all further discharging operations, the drive gas acts by way of the driving piston on the contents of the container. Obviously, the extensions provided for the lock means may also be made of such a length that even when the container has been partly discharged, they can still be gripped from the outside and reengaged so that in this way the contents still stored in the container can be relieved of pressure after each time that the container has been used, and so that the bag insert may possibly be retracted by means of the extended portions to its starting position when the container has been completely emptied, so that the container with insert can again be used for discharging further material introduced into the container.

It is further advantageous for the peripheral edges of the piston to be provided with sealing lips or to be formed as sealing lips. In this way, there is always a sufficient seal between the space in which the contents of the container are contained, and the space in the container which is separated from the contents by the piston and which is occupied by the bag insert loaded by the gas pressure, even when the container is not completely cylindrical and the piston does not move completely coaxially in the container.

The driving piston desirably has a cylindrical cavity to accommodate the bag together with the container bottom, before the container is put to use. Thus, when the container is completely full, the bag insert disappears in the folded condition into this cavity in the piston and therefore requires the minimum amount of space. This cavity is desirably of such a size that the lower edge of the piston lies substantially against the container bottom so that the gas pressure in the bag insert only acts on the peripheral wall of the hollow piston but not on the wall of the container, so that its cross section can be made extremely small. In this case, it is possible for the bag containing the pressure medium to be of a smaller cross section than the cavity in the driving piston so that the pressure force acting on the material to be discharged can be favorably selected to correspond to the nature of such material.

The gas used to fill the container insert can be impure, and therefore cheap, gases as the above proposed construction prevents any mixing of the gas and the filling material. Instead of hook-shaped or spherical ends for locking the extensions forming the mechanical lock means for the bag insert, snap-locking or bayonetlike means can also be used, or for example tearoff foils can be provided, by means of which the lock means can be particularly easily released. Assembly of the container according to the invention, which is preferably only in two parts, can be effected particularly simply when the bag insert is arranged to be engaged into the container without requiring any screw or welded connection. The driving gas charge can also be introduced into the bag insert after it has been fitted into the container, this being effected for example at the same time as the contents are introduced into the container by way of its delivery aperture.

A number of embodiments given by way of example of a tubular container in accordance with the invention are shown in diagrammatic form in the accompanying drawing, in which:

FIG. 1 shows a cross-sectional exploded view of the insert to be fitted into the container, comprising a driving piston, a bag containing pressure gas, a container bottom and lock means,

FIG. 2 shows the same insert in the compressed and locked but ready-for-use condition,

FIG. 3 shows a container according to the invention with fitted and compressed insert, with the lock means holding the bag,

FIG. 3a shows the same container as FIG. 3 but after it has been put to use, that is with the bag in the released condition after the stored material has already been partly discharged,

FIG. 4 shows another embodiment of the upper part of the insert,

FIG. 5 shows the lower part of the container with another form of the bag lock means, and

FIG. 6 shows a further embodiment of the upper region of the insert.

As shown in FIG. 1, the insert 1 comprises a driving piston 2, into a cavity 3 in which is fitted a bellows-shaped bag 4 containing drive gas, the drive gas being fed to the bag 4 by way of a gas filling connection 5 in a container bottom 6. The container bottom 6 has holes 7 for accommodating hook-shaped extensions 8 on the piston 2, for the purpose of initial locking.

FIG. 2 shows that, with the bag 4 still compressed and the piston 2 in the locked condition at the container bottom 6, the insert 1 contains, the remaining space, gas 10 which is in liquefied form and which is prevented from premature vaporization by the locking action of the extensions 8. The liquid drive gas 10 is introduced by way of the gas filling connection 5 which is then sealed with a closure member 11.

As shown in FIG. 3, the above described insert is fitted at the base of a container 14 which contains material 15. When the extended portions 8 are released, the bag 4 of the insert 1 unfolds and, owing to the gas pressure therein, urges the material 15 towards the delivery aperture of the container 14 by way of the piston 2. To seal the piston 2 which moves upwardly to displace the material 15, the piston 2 carries a strong wedge-shaped outwardly extending peripheral sealing lip 20 with one or more sealing flanges 21 below it, while below the sealing flanges 21 is a guide shoulder 22 of substantially smaller diameter. The function of these sealing members is clearly apparent from FIG. 3.

In the embodiment shown in FIG. 4, the extensions for mechanically locking the bag 4 are provided on a plate 18 arranged on the head 16 of the bag 4 and terminate in spherical ends 13 which engage in wedge-shaped slots provided in the container bottom when the bag 4 is still compressed. The piston 12 which is separate from the bag 4 preferably comprises resilient material.

In the embodiment shown in FIG. 5, with the bag 4 in the folded condition the extensions 8 provided for locking purposes engage with their downwardly extending hooks into recesses 17 provided on both sides in the wall of the container 14 in the lower region thereof.

As shown in FIG. 6, the drive gas bag 25 is made with a smaller outside diameter than the cavity 3 in the piston 2 into which the gas bag 25 is inserted with its upper end cup 26.

In all the embodiments shown, the delivery aperture in the container and the closure member which is in any case required and which is opened each time that material is to be discharged from the container, are not shown as these parts are not the subject of the present invention and may be of conventional form (c.f. the French specification mentioned above).

Claims

I claim:

1. A hollow cylindrical container for storing and delivering fluid material, said container comprising a hollow cylindrical casing, a piston axially slidable in said casing to urge said material towards one end of said casing for delivery, a casing end member for the other end of said casing, a foldable bag containing pressurized gas extending axially in said casing between said piston and said casing end member for urging said piston towards said one end of said casing, and externally releasable mechanical lock means extending longitudinally of said casing outside said bag and preventing axial expansion of said bag until said lock means is released, at least said casing end member, said foldable bag and said lock means forming an insert adapted to be fitted into said casing.

2. A container according to claim 1, wherein said piston is part of said insert.

3. A container according to claim 2, wherein said lock means comprises at least one axially extending extension on said piston engageable at the free end thereof in at least one hole or recess in said casing.

4. A container according to claim 2, wherein said lock means comprises at least one axially extending extension on said piston engageable at the free end thereof in at least one hole or recess in said casing end member.

5. A container according to claim 1, wherein said bag has a headplate adjacent said piston and said lock means comprises at least one axially extending extension on said headplate.

6. A container according to claim 1, wherein said piston has sealing lips thereon.

7. A container according to claim 1, wherein said piston has a cylindrical cavity to accommodate said bag and said casing end member before the container is used.

8. A container according to claim 7, wherein said bag has a substantially smaller cross section than said cavity.