Fluid dispenser

Abstract

A fluid dispenser comprising: a fluid reservoir (1); and a pump (3) comprising a pump body (30) and an actuator rod (34), defining between them a pump chamber (33) having a predetermined maximum volume, the rod (34) being axially movable in the body (30) so as to vary the volume of the pump chamber (33); the dispenser being characterized in that it further comprises a dispenser cannula (5) that is mounted on the actuator rod (34) and that includes a dispenser outlet (52) that is suitable for forming a drop of fluid that separates from the cannula (5) by gravity, the determined maximum volume of the pump chamber (33) being substantially equal to the volume of the drop of fluid that is dispensed at the dispenser outlet (52).

Claims

1. A fluid dispenser comprising: a fluid reservoir containing a fluid dispensable in drops; a pump comprising a pump body and an actuator rod, defining between them a pump chamber having a predetermined maximum volume, the rod being axially movable in the body so as to vary the volume of the pump chamber; and a dispenser cannula that is mounted on the actuator rod and that includes a dispenser outlet that is configured to form a drop of the fluid that separates from the cannula by gravity, the determined maximum volume of the pump chamber being substantially equal to the volume of the drop of fluid that is dispensed at the dispenser outlet.

2. The dispenser according to claim 1, wherein the dispenser cannula defines a predetermined internal volume that corresponds to about 3 to 7 times the maximum volume of the pump chamber.

3. The dispenser according to claim 1, wherein the dispenser cannula is made out of a transparent material.

4. The dispenser according to claim 1, wherein the cannula is elongate, thereby presenting a general configuration of a pipette.

5. The dispenser according to claim 1, including a pusher for actuating the pump, the pusher being secured to the reservoir.

6. The dispenser according to claim 1, including a casing in which the reservoir is slidably mounted, the cannula being secured to the casing.

7. The dispenser according to claim 6, wherein the casing includes an open trailing end in which a pusher is axially movable, and a leading end in which the cannula is mounted in stationary manner, projecting axially with its dispenser outlet, the pusher, during actuation, moving the reservoir and the pump body in the casing, compressing a return spring.

8. The dispenser according to claim 1, wherein the reservoir includes a follower piston that moves as fluid is extracted from the reservoir.

9. The dispenser according to claim 1, wherein the maximum volume of the pump chamber lies in the range about 50 mL to about 70 mL.

10. The dispenser according to claim 3, wherein the transparent material is glass.

11. The dispenser according to claim 6, wherein the cannula is secured to the casing by bi-injection with the casing.

12. The dispenser according to claim 1, wherein the dispenser cannula defines a predetermined internal volume that corresponds to about 4 to 6 times the maximum volume of the pump chamber.

13. The dispenser according to claim 1, wherein the drop of fluid is dispensed from the cannula at a distal end of the cannula.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The present invention is described more fully below with reference to the accompanying drawings, which show an embodiment of the present invention by way of non-limiting example.

(2) In the figures:

(3) FIG. 1 is a vertical section view through a fluid dispenser of the invention; and

(4) FIG. 2 is a larger-scale view of the bottom portion of FIG. 1.

DETAILED DESCRIPTION

(5) The dispenser shown in the figures comprises six component elements, namely: a reservoir 1; a pusher 2; a pump 3; a fastener ring 4; a dispenser cannula 5; and a casing 6. All of the component elements are disposed on a longitudinal axis X: some component elements may be circularly symmetrical around the axis X.

(6) The fluid reservoir 1 includes a cylindrical slide cylinder 11 inside which a follower piston 12 is slidably mounted. When the reservoir is full, the piston 12 is situated at one end of the cylinder 11, remote from the other end that forms a neck 13. A volume is thus constituted of capacity that varies as the follower piston 12 is moved inside the slide cylinder 11. With this type of reservoir, the fluid contained in the reservoir is always protected from the outside air, and thus cannot deteriorate.

(7) The pusher 2 is disposed at the end of the slide cylinder 11 that is remote from the neck 13, i.e. just above the follower piston 12, when the reservoir is full of fluid. The pusher 2 is secured to the cylinder 11. In a variant, the pusher 2 may even form an integral part of the cylinder 11 or of the reservoir 1. Thus, by pressing on the pusher 2, pressure is exerted on the reservoir 1, as described below.

(8) The pump 3 is fastened in the opening 13 of the reservoir by means of a fastener ring 4. The pump 3 includes a pump body 30 that internally forms a pump chamber 33 of variable capacity, but defining a predetermined maximum volume in the rest position. The pump is defined by the pump body 30, but also by an actuator rod 34 that is axially movable inside the pump body. By way of example, the actuator rod 34 may be provided with a piston that slides in leaktight manner inside the pump body 30. The pump 3 is provided with an inlet valve 31, and with an outlet valve that may be incorporated in the actuator rod 34, or secured thereto. Thus, by pressing on the actuator rod 34, the volume of the pump chamber 33 varies from its maximum volume that may lie in the range about 50 mL to about 70 mL. The actuator rod 34 is movable from its rest position, against a return spring 35 that is situated outside the pump chamber 33. The dispensed dose of fluid product substantially corresponds to predetermined maximum volume of the pump chamber. In other words, the pump dispenses at each actuation substantially the whole of the fluid product present in the pump chamber. The spring 35 thus returns the pump chamber 33 into its predetermined maximum-volume configuration. This design is entirely conventional for a manual pump in the fields of perfumery, cosmetics, or even pharmacy, except for the spring 35 that is situated outside the pump chamber.

(9) The dispenser cannula 5 may be made out of a transparent material, such as glass or a plastics material, for example. The cannula 5 may present perfect circular symmetry around the axis X. The cannula 5 includes a connection sleeve 53 that is engaged around the free end of the actuator rod 34 of the pump 3. The cannula 5 then forms a main elongate cylindrical section 51 that defines a predefined internal volume 54. At its end, the cannula 5 forms a dispenser outlet 52 that is suitable for forming a drop of fluid that separates from the cannula by gravity. The volume of the drops that are dispensed lies in the range about 50 mL to about 70 mL, just like the predefined maximum volume of the pump chamber 33. The dispenser cannula 5 presents a generally elongate configuration, similar to a conventional pipette. The internal volume of the cannula 5 corresponds to about 3 to 7 times, and preferably 4 to 6 times, the maximum volume of the pump chamber 33 that lies in the range about 50 mL to about 70 mL. In other words, the internal volume of the cannula lies in the range about 150 mL to about 500 mL. Preferably, the internal volume lies in the range about 200 mL to about 400 mL, and is preferably 300 mL. Thus, the content of the pump chamber 33 that is driven under pressure through the actuator rod 34 arrives in the cannula that is already full of fluid. The considerably-greater volume of the cannula relative to the dose that is dispensed makes it possible to create considerable head loss in the cannula, thereby making it possible to avoid fluid being dispensed in the form of spray. The fluid is thus damped in the cannula prior to being detached therefrom by gravity in the form of a drop having a capacity that lies in the range about 50 mL to about 70 mL.

(10) The casing 6 constitutes a hollow shell 61 in which there is housed the reservoir 1, the pump 3, and a portion of the cannula 5. The casing 6 includes an open top end in which the pusher 2 is situated, and a bottom end that is extended by the cannula 5 that is mounted in stationary manner inside a head portion 65 of the casing 6: the casing and the cannula may be made as a single part, e.g. by bi-injection. The reservoir 1, the pump body 30, and the fastener ring 4 are axially movable down and up inside the casing 6 by pressing on the pusher 2, thereby causing the spring 35 to compress. In this way, the user may take hold of the dispenser in the palm of one hand via the casing 6, and press on the pusher 2 by means of the thumb. Actuation is thus similar to the actuation of a conventional pipette. Given that the casing 6 completely masks the reservoir 1 and the pump 3, the user is not even conscious of actuating a pump by pressing on the pusher 2. The user merely observes that by pressing on the pusher 2, a well-formed drop of fluid falls by gravity from the end of the cannula 5.

(11) The correct operation of the dispenser comes from matching capacity between the pump chamber and the drop that is dispensed, and from the large internal volume of the cannula that serves as a fluid damping chamber before the drop is formed.