WO2010105641A1

WO2010105641A1 - Dispensing device for a fluid substance enclosed in a container

Info

Publication number: WO2010105641A1
Application number: PCT/EP2009/002022
Authority: WO
Inventors: Matteo Moretti
Original assignee: Lumson S.P.A.
Priority date: 2009-03-19
Filing date: 2009-03-19
Publication date: 2010-09-23

Abstract

A dispensing device for a fluid substance enclosed in a container comprising a cup-shaped body closed by a ring cap and presenting an end at which a passageway is provided for dipping into fluid to be dispensed, said ring cap presenting a hole through which a stem for operating a piston is inserted and slides, said piston presenting a lower seal lip and an upper lip which sealedly slides along the inner surface of the cup-shaped body, which presents on its inner surface first and second means cooperating respectively with the first and second lip to connect the lower chamber to the upper chamber when the piston is in a lower end-of-stroke position, in order to enable the air contained in the lower chamber to escape during priming.

Description

DISPENSING DEVICE FOR A FLUID SUBSTANCE ENCLOSED IN A CONTAINER

The present invention relates to a dispensing device for a fluid substance enclosed in a container.

In particular, the fluid substance is a medicament, a perfume, a cream or the like which has preferably to be maintained isolated from air (and hence from any type of contamination) until the moment in which it is dispensed, especially within that portion of the stem upstream of the dispensing hole and downstream of the compression chamber.

Pumps are known, for example from EP0803294, presenting at the top of the stem an operating pushbutton comprising a device or mechanism for hermetically sealing the dispensing hole (when at rest), such as to maintain isolated from the external environment the product to be dispensed, which is contained in the stem. Operating the pushbutton opens of the dispensing hole, which recloses automatically when dispensing has taken place. It is well known that pumps of any type have to be primed. On initially operating the pump mounted on the container filled with liquid, the compression chamber has to be filled with this liquid in order to be able to dispense it. The air present in the chamber has to be replaced by the liquid. The initial operation of the pump by pressing the dispensing pushbutton compresses the air in the chamber. This air has to be expelled from the chamber (usually via the stem bore which is usually in communication with the outside), to enable a vacuum to be created, with consequent drawing of the liquid from the container. However the pressure of this air compressed by the piston stroke is insufficient to open the conventional valve means provided between the compression chamber and the stem bore. Mechanical means are therefore provided which, when the piston is in its end-of-stroke position, open these valve means to hence enable the compressed air to escape through the stem.

If a pushbutton such as that described in said European patent application (or the like) is applied to the top of the stem, the air cannot escape through its bore, as it is not freely connected to the external environment.

In a known technique applied to such dispensing devices, the air is made to escape by using for example the method described in PCT/EP2005/056754.

This patent application describes projections or recesses provided on the inner surface of the cup-shaped body to deform the lower lip of the piston when in its lower end-of-stroke position, hence enabling the air to escape to the top of the cup-shaped body which is in communication with the container interior.

It can happen that during the use of the pump, a variation is noted in the product quantity dispensed due to air entry into the compression chamber, which seeps into this latter from the lower seal lip when the pump is in the draw- in stage with a vacuum in the compression chamber to draw the fluid into its interior from the container; in this respect, the lower lip, given its shape, provides an excellent seal during compression, but is unable to provide a perfect seal during draw-in

An object of the present invention is to provide a pump which overcomes the technical drawbacks of the known art, in particular presenting better continuity in the fluid quantity dispensed.

This and other objects are attained by a pump formed in accordance with the technical characteristics of the accompanying claims.

The structure and characteristics of the pump according to the invention will be more apparent from the description of one embodiment thereof given by way of non-limiting example with reference to the accompanying drawings, in which: Figures 1 and 2 are longitudinal sections through a pump shown respectively in the rest state at the beginning of the dispensing stage, and at the end of its dispensing stroke;

Figures 3 and 4 are enlarged cross-sections through the pump taken respectively on the lines 3-3 and 4-4 of Figure 2; and

Figures 3A and 4A show on an enlarged scale that portion bounded by a dashed circle in Figures 3 and 4 respectively.

The dispensing device of the present invention is indicated in the said figures by the reference letter D. These show a dispensing device (or pump for brevity) the general structure of which is of known type, except for the details illustrated hereinafter. To give a specific example, the pump has a structure totally similar to that of the devices illustrated in the prior patents specifically stated in the introductory part of this description, the teachings of which are incorporated herein for reference: the structure and operation of the pump will therefore not be described in detail herein for brevity.

The pump comprises a cup-shaped body 1 closed at one end by a ring cap 2 and presenting at its other end a hole 3 which opens into the hollow space defined by a container (not shown in the drawings), on the mouth of which the pump ring cap 2 is sealedly mounted in any known manner (for example, by clinching, threaded coupling or in other manner).

Translatable within the cup-shaped body 1 there is an annular piston 4 having a lower lip 4A which seals against the inner surface of the cup-shaped body and, respectively, an annular lip 4C which is translatable along and seals against the inner surface of an annular seat 5A provided on an internally hollow stem 5, on the free end of which an operating and dispensing pushbutton of known type is mounted, provided with a valve means for isolating the stem interior upstream of said hole. The pushbutton is for example that described in EP0803294 or EP0686433.

The stem 5 is translatable axially and is inserted through a hole provided in the flange 2. The fluid substance can be conveyed along the stem bore towards the dispensing hole B1 and then expelled to the outside, the fluid substance having been previously drawn into a pump lower chamber 8 located below the lower surface of the piston 4 (its lower lip 4A) and the draw-in hole 3 of the pump, where a unidirectional valve 11A is housed consisting of a ball 11 movable between a seal seat provided at the upper end of the hole 3 and a cage 13 forming part of the pump body, or consisting of another seal element. An important characteristic of the present invention is that the piston 4 further presents an upper lip 4B which sealedly slides along the inner surface of the cup-shaped body. The upper and lower lip, the central body of the piston 4 and that wall of the cup-shaped body lying between the lips define an annular chamber of small and negligible volume.

The upper part of the piston 4 with its upper lip 4B, the cup-shaped body 1 and the ring cap 2 define an upper chamber 9 (well visible in Figure 2) which is in communication with the outside of the cup-shaped body 1 via a hole or passageway 10 provided directly in this latter: in this manner, when the pump is mounted on the mouth of a container, the pressure in the pump upper chamber 9 is always equal to the pressure inside the container on which the pump has been sealedly mounted (i.e. to the pressure existing outside the cup-shaped body 1). The piston 4 is slidable on the stem in conventional manner and can assume a first position in which it hermetically closes a passageway connecting the stem bore to the lower chamber, and a second (dispensing) position in which it leaves this passageway open. Optionally a spring can be provided between a collar 70 of the stem and the piston.

For any utilization or rest state of the pump there exists a hermetic seal between the outer surface of the stem 5 and the opposing surface of the hole in the ring cap 2 through which the stem extends and is translatable, it being provided, in the case of the construction shown in the figures, by an O-ring 12 of rubber or suitable elastomeric material (even though evidently the seal between the stem and the ring cap hole can be provided in a different manner, for example simply by one or two lips forming part of the ring cap 2, which can be made of deformable plastic material, such as polyethylene, polypropylene, etc. In the pump of the present invention, the hollow stem 5 is always housed and translatable under sealed conditions (for any state of utilization or rest of the pump) within the guide hole through the ring cap 2, in the cup-shaped body 1 of the pump there being provided the hole or passageway 10 at the upper chamber 9 of the pump body.

The result is that as the pump upper chamber 9 cannot let liquids, air or gas leak between the outer surface of the stem 5 and the ring cap hole through which this stem extends, there are no undesirable leakages or seepages of product in the gas phase, of air or fluids between the stem 5 and the gasket 12 of the ring cap 2, if the ring cap 2 is mounted hermetically to seal against the mouth of a container (not shown for simplicity). It is also found that the pressure inside the upper chamber 9 of the pump 8 is always equal (by virtue of the presence of the passageway 10) to the pressure within the container on which the pump has been hermetically mounted. Hence, assuming that the pump is sealedly mounted on the mouth of a known container closed at its other end by a movable endpiece which moves gradually as the substance enclosed in the container is dispensed, air cannot penetrate into the container under any condition of utilization, such that the product or substance contained therein is not contaminated by air or cannot harden or dry. The same occurs if the pump is mounted on a deformable bag which is squeezed by the atmospheric pressure, or if it is associated with a container in which low boiling liquid is present as described in PCT/EP2005/056754.

The operation of the pump in question is totally apparent to an expert of the art and can also be found on reading PCT/EP2005/056754.

The dispensing device described herein presents, on the inner surface of the cup-shaped body, first means 100 and second means 200 to cooperate respectively with the lower lip 4A and the upper lip 4B to create, when the piston 4 is in an end-of-stroke position or close thereto, a passageway which connects the lower chamber 8 to the upper chamber 9, and consequently enables the compressed air in the lower chamber to escape at the pump priming stage during initial use. Essentially, these means can be either projections, such as those visible in Figures 3A and 4A, which deform the lip (4A, 4B) superposed on them to hence form an interruption in its seal against the cup-shaped body, or passageways (not shown) provided in the cup-shaped body, which prevent the piston lips from sealing against the wall of the cup-shaped body 1 when these lips are superposed on them.

Advantageously the first means 100 and second means 200 and the piston stroke are regulated such that when the piston is in its lower end-of-stroke position both the first and the second lip are superposed on the first and on the second means respectively, whereas when the piston is in its upper end-of- stroke position the second means 200 are positioned between the lower lip and the upper lip, without interfering with either of the two lips. This ensures the seal of the upper lip 4B during its entire stroke (with the exception of when the piston is in the end-of-stroke position).

It should be noted that in the present solution, the seal of the third piston lip against the stem is achieved in a particular manner. For this, as already described, the stem comprises an annular seat 5A in which the third lip 4C seals in any position in which the piston lies relative to the stem. Specifically, the third piston lip is shaped such as to seal against the inner surface of the annular seat. Any dimensional variation (expansion) of the third lip due to external factors hence does not compromise the seal, which instead is improved.

In the described pump the lower end-of-stroke position (delivery) of the piston is defined by the contact between the piston and a step 80 provided in the cup- shaped body. However the lower end-of-stroke position can be defined by any other equivalent means known to an expert of the art. In an alternative embodiment of the device in question, it is not essential to isolate the container interior on which the pump is fixed from the outside environment. Consequently no seal is provided between the ring cap and the stem, or rather there exist certain stem positions in which this seal is not ensured (for example in the end-of-stroke position). In this embodiment, compressed air escape from the lower chamber 8 during priming takes place towards the outside, seeping between the ring cap and the stem. In said embodiment the passage 10 is not essential.

In an alternative embodiment, the seal of the third piston lip can be achieved directly against the outer surface of the stem on which the piston is mounted.

Claims

1. A dispensing device for a fluid substance enclosed in a container comprising a cup-shaped body closed by a ring cap and presenting an end at which a passageway is provided for dipping into fluid to be dispensed, the passageway being intercepted by a unidirectional valve, said ring cap presenting a hole through which a stem for operating a piston is inserted and slides, said piston presenting a lower seal lip which with the cup-shaped body defines a lower chamber, said stem presenting a bore which communicates with the lower chamber at least during a product dispensed stage, on the stem there being provided a piston operating pushbutton having a valve means for isolating the stem interior upstream of the dispensed hole from the external environment, characterised in that said piston presents an upper lip which sealedly slides along the inner surface of the cup-shaped body and defines with the cup- shaped body and the ring cap an upper chamber, said cup-shaped body presenting on its inner surface first and second means cooperating respectively with the first and second lip to connect the lower chamber to the upper chamber when the piston is in a lower end-of-stroke position, in order to enable the air contained in the lower chamber to escape during priming.

2. A device as claimed in claim 1 , characterised in that said first and/or second means comprise at least one passageway arranged to break the seal of the respective lip when this is superposed on the passageway.

3. A device as claimed in claim 1 , characterised in that said first and/or second means comprise at least one projection arranged to break the seal of the respective lip by deforming it when this is superposed on the projection.

4. A device as claimed in one or more of the preceding claims, characterised in that the distance between said first and second lip and the stroke of the piston are regulated such that when the piston is in an upper end- of-stroke position the lower lip assumes a position between said first and said second means.

5. A device as claimed in claim 1 , characterised in that said stem presents a collar against which a spring located between said collar and said piston acts, the piston being sealedly slidable on said stem.

6. A device as claimed in claim 1 , characterised in that said lower end-of- stroke position is defined by the contact of said lower lip with a step provided in said cup-shaped body.

7. A device as claimed in one or more of the preceding claims, characterised in that said device is able to be associated with a container in which said fluid is sealedly contained against the outside, said stem sealedly sliding through said hole for its entire length, the upper chamber communicating with the container interior when said device is positioned on said container such that, when said piston is in an end-of-stroke position, air escape takes place towards the container interior.

8. A device as claimed in claim 7, characterised in that said seal between said ring cap and said stem is established by an O-ring.

9. A device as claimed in one or more of the preceding claims, characterised in that said stem presents an annular seat in which a third lip of said piston is sealedly inserted, the seal being established between the outer surface of said lip and the inner surface of said seat.