Fluent material handling – with receiver or receiver coacting mea – Processes – Filling dispensers
Reexamination Certificate
2000-03-17
2001-06-05
Douglas, Steven O. (Department: 3751)
Fluent material handling, with receiver or receiver coacting mea
Processes
Filling dispensers
C141S018000, C141S027000, C222S321700
Reexamination Certificate
active
06240979
ABSTRACT:
The present invention relates to a method of filling a dispenser with a fluid to be dispensed, especially a pasty material, said dispenser comprising a head piece and a fluid container with a filler opening which is closed by said head piece when the fluid has been filled into the fluid container. The present invention additionaly relates to a fluid dispenser, in particular for pasty material, comprising a head piece which is attached to a fluid container thus closing a filler opening of said fluid container.
Dispensers of the above-mentioned type are suitable for dispensing flowable fluid media, including pastes.
In filling machines, which are used for filling a dispenser, filling tolerances occur and, as a consequence, slightly different filling levels in the storage container containing the medium in the dispenser. In the case of dispensers which are filled from the head side and then closed by the head piece containing the transport mechanism, air may remain in the storage chamber of the fluid container when the filling volume is at the lower limit of the tolerance range (minimum filling quantity); when the dispenser is used later on, this air may penetrate into a dispensing channel where it may cause interruptions in the flow of the medium to be dispensed. The user will feel this to be annoying, and in cases of use where a precise dosing behaviour is of essential importance, e.g. when the media dispensed are pharmaceutical products, these interruptions may cause substantial difficulties.
When the filling volumes are at the upper limit of the tolerance range (maximum filling quantity), the danger exists that, when the dispensing head is attached to the storage container, medium may be forced out either between the storage container and the dispensing head or through the dispensing head itself.
A method of filling a dispenser as well as a dispenser of the type cited at the start are known from EP-A-263 995. Overfilling of the storage container is there compensated by a deformation of a follow-up piston arranged in said storage container. When the filling volume is at the lower variation limit, air may, however, penetrate into a dispensing channel.
Since the follow-up piston of the known dispenser undergoes a change of shape in response to overfilling, it is, moreover, not possible to fill a defined space within the dispensing head with medium so that, e.g. in pumping dispensers, material will be dispensed only after several idle strokes.
Hence, it is the object of the present invention to improve a method and a fluid dispenser of the type cited at the start in such a way that, also with due regard to the filling tolerances of the filling machine, smooth filling of the dispenser resulting in improved functional properties thereof is achieved, and a dispenser is provided, which is more convenient to use.
In the case of a method cited at the start, the present invention solves this task by the features that, when the head piece is being attached to a fluid container, a projecting area of said head piece will first come into sealing contact with the fluid and that, when airtight sealing of a storage chamber of the fluid container has been established by the head piece and when said head piece is pushed onto the fluid container still further by a predetermined displacement distance for moving said head piece to an end position on the fluid container, fluid will be displaced from said fluid container into a discharge channel of the head piece.
When the head piece is being attached, a projecting area of said head piece first comes into contact with the medium in the fluid container and dives into said medium. Until the point of airtight sealing between the head piece and the fluid container is reached, air, which is located on top of the material to be dispensed, will be displaced from the storage container. Due to the fact that the movement of the head piece is continued and due to the predetermined fixed displacement distance, the content of the fluid chamber, (preferably a pasty mass) is compressed. Fluid can thus be pressed into a pump chamber and into the fluid dispensing channel of the head piece; said fluid does, however, not reach the dispensing opening of the fluid dispensing channel. By purposefully dimensioning the displacement distance and the resultant volume displacement in a pumping dispenser, the pump chamber and, if desired, also part of a downstream discharge channel following said pump chamber and leading to the dispensing outlet can be filled with fluid for the first time in this way, so that a controlled amount of fluid can already be dispensed by the first dispensing stroke or a dispensing stroke following the first one according to a preferred embodiment of the present invention. The displacement distance is chosen such that a fluid inlet opening of the head piece, which is adapted to be connected to the dispensing outlet, will always remain immersed in the fluid.
For compensating filling tolerances of a filling device and for guaranteeing continuous dispensing of the dispenser, a filling level is adjusted in the fluid container during filling of said container in such a way that the volume which will be displaced when the head piece is attached lies between a predeterminable maximum value and a minimum value until the point of first airtight sealing has been reached. Overfilling on the one hand and inclusions of air in the head piece on the other will be avoided in this way.
Further preferred embodiments of the method according to the present invention are disclosed in the associated subclaims.
According to the present invention, the task stated hereinbefore with regard to the dispenser is solved in the case of a dispenser of the type cited at the start by the features that the head piece is provided with a tubular chimney portion which projects into a storage chamber of the fluid container and the fluid displacement volume of which corresponds at least to a volume of a pump chamber of the head piece.
This structural design ensures not only a compensation of filling tolerances of the filling machines but also a reliable prefilling of a defined part of the discharge channel in the head piece including a transport means, such as a pump chamber. In addition, air is prevented from penetrating into the discharge channel of the head piece and squeezing out of fluid from the dispenser when the dispensing head is being attached is avoided as well.
In accordance with a preferred embodiment of the dispenser, an annular groove for accommodating a container wall of the fluid container is provided on the bottom side of the head piece, said container wall surrounding the filler opening and the groove depth of said annular groove corresponding at least to the predeterminable displacement distance when seen in relation to the position of an upper edge of this container wall when the point of airtight sealing has been reached for the first time and at an end position existing when the dispenser has been fully mounted. This permits a structurally simple solution for achieving the predeterminable displacement distance. The annular groove and the upper edge fulfil simultaneously the function of sealing the fluid chamber and allow a displacement of the head piece relative to the fluid container beyond the point of first airtight sealing of the storage chamber up to and into the locked end position of the head piece on the fluid container.
A locking device for securing the end position is provided perferably between the head piece and the fluid container. This locking device can be provided in the area of the upper edge on the one hand and the annular groove on the other, where it can be produced in a particulary simple manner, and it can be implemented e.g. as a snap-in connection. On the one hand, this snap-in connection fulfils a fastening function and, on the other hand, it will secure the head piece in position on the fluid container in the fully mounted condition of the dispenser, i.e. at the end position of the fully mounted head piece.
Instead of securing the head piece
Douglas Steven O.
Laubscher & Laubscher
RPC Wiko GmbH & Co. KG
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