Liquid dosing device

Abstract

A liquid dosing device for dispensing a metered dose of liquid from a squeezable container, comprising an outlet passage leading to a discharge opening; a dosing chamber positioned behind said discharge opening and having at least one entrance opening allowing a charging flow of liquid from said container into said dosing chamber under the influence of weight of liquid, and a drive opening allowing a control flow of liquid from said container into said dosing chamber in response on a rise of pressure of liquid in the squeezable container; a floating plunger movably arranged in the dosing chamber so as to advance upon said rise of pressure from a rest position in which under the influence of a lifting force of buoyancy said floating plunger closes said drive opening, into a blocking position in which said floating plunger blocks said outlet passage, wherein said floating plunger when advancing into said blocking position, pushes said liquid charged into said dosing chamber, to said outlet passage; a stop seat upon which said floating plunger acts in its blocking position, and a sealing lip for closing said outlet passage, being arranged such that a seat-sided portion of the floating plunger or a plunger-sided portion of the stop seat and said sealing lip is formed, particularly injection-mold, of one single piece of the same plastic material.

Claims

1. A liquid dosing (1) device for dispensing a metered dose of liquid from a squeezable container, comprising: an outlet passage (16) leading to a discharge opening (17); a dosing chamber (11) positioned behind said discharge opening (17) and having at least one entrance opening (19) allowing a charging flow of liquid from said container into said dosing chamber (11) under the influence of weight of liquid, and a drive opening (15) allowing a control flow of liquid from said container into said dosing chamber (11) in response on a rise of pressure of liquid in the squeezable container; a floating plunger (39) movably arranged in the dosing chamber (11) so as to advance upon said rise of pressure from a rest position in which under the influence of a lifting force of buoyancy said floating plunger (39) closes said drive opening (15), into a blocking position in which said floating plunger (39) blocks said outlet passage (16), wherein said floating plunger (39) when advancing into said blocking position, pushes said liquid charged into said dosing chamber (11), to said outlet passage (16); a stop seat (55) upon which said floating plunger (39) acts in its blocking position, and a sealing lip (59) for closing said outlet passage (16), being arranged such that a seat-sided portion of the floating plunger (39) or a plunger-sided portion of the stop seat (55) and said sealing lip (59) is formed, particularly injection-mold, of one single piece of the same plastic material.

2. A liquid dosing device (1) according to claim 1, wherein said sealing lip (59) protrudes from said seat-sided portion of the floating plunger (36) or from said plunger-sided portion of said stop seat (55) particularly by at least 1 mm, wherein particularly the sealing lip (59) comprises a lip body (54) comprising an annular foot portion (58) merging in the seat-sided portion or in the plunger-sided portion in continuously extending to an annular sealing end (60) forming a circumferentially closed sealing contact with the other seat-sided portion of the floating plunger (39) or the plunger-sided portion of the stop seat (55), wherein particularly the cross-section of said lip body (54) from said annular foot portion (58) to said sealing end (60) continuously reduces.

3. A liquid dosing device (1) according to claim 1, wherein said sealing lip (59) extends from said seat-sided portion of the floating plunger (39) or said plunger-sided portion of the stop seat (55) in a radial direction, wherein particularly the sealing lip (59) formed unitarily with said seat-sided portion of the float plunger (39) extends radially outwardly towards said stop seat (55) or said sealing lip (59) unitarily formed with said plunger-sided portion of the stop seat (55) extends radially inwardly towards the floating plunger, wherein particularly the radial extension of the sealing lip (59) unitarily formed with the seat-sided portion of the float plunger (39) is dimensioned such that a sealing end (60) of the sealing lip (59) is positioned vis-à-vis an annular edge of said plunger-sided portion of the stop seat (55) in the blocking position.

4. A liquid dosing device (1) according to claim 1, wherein said sealing lip (59) particularly formed unitarily with said plunger-sided portion of the stop seat (55) defines a particularly circular orifice.

5. A liquid dosing (1) device according to claim 1, wherein the sealing lip (59) is elastically deformable provides an elastic elongation in axial direction, particularly defined by the axial extension of the outlet passage (16), particularly ranging up to 1.0 mm, preferably from 0.4 mm to 1.5 mm, wherein particularly said elastic elongation is at least 0.02 mm or at least 0.1 mm, particularly in a range of 0.02 mm to 0.3 mm, when said floating plunger (39) acts on said sealing lip (59) by a force of pressure of 2 N or 1 N, particularly said elastic elongation being at least 0.15 mm. or at least 0.2 mm, particularly in a range of 0.15 mm to 0.4 mm, if a force of pressure of 4 N or 2 N is applied, particularly said elastic elongation being at least 0.3 mm or at least 0.4 mm, particularly in a range of 0.2 mm to 0.7 mm, if a force of pressure of 10 N, 8 N or 6 N is applied, particularly said elastic elongation being at least 0.5 mm or at least 0.6 mm, particularly in a range of 0.4 mm to 0.9 mm, if a force of pressure of 20 N or 15 N is applied, particularly said elastic elongation being at least 0.6 mm or at least 0.8 mm, particularly in a range of 0.6 mm to 1.2 mm, if a force of pressure of 30 N or 25 N is applied, particularly said elastic elongation being at least 0.8 mm or at least 0.9 mm, particularly in a range of 0.8 mm to 1.4 mm, if a force of pressure of 50 N or 40 N is applied, particularly said elastic elongation being at least 0.9 mm or at least 1.0 mm, particularly in a range of 0.9 mm to 1.7 mm, if a force of pressure of 60 N or 70 N is applied.

6. A liquid dosing device (1) according to claim 1, wherein said sealing lip is designed such that an axial restoring force of more than 0.4 N is delivered by the sealing lip (59) in case of an elastic elongation of said sealing lip of at least 0.1 mm, 0.2 mm or 0.3 mm, and/or a restoring force of more than 2 N or 2.5 N in case of an elastic elongation of said sealing lip (59) of more than 0.2 mm or 0.3 mm, and/or a restoring force of more than 3 N, 4 N or 5N in case of an elastic elongation of at least 0.3 mm or 0.4 mm, and/or a restoring force of more than 6 N, 8 N or 10 N in case of an elastic elongation of at least 0.5 mm or 0.6 mm, and/or a restoring force of more than 10 N or 15 N in case of an elastic elongation of at least 0.6 mm, 0.7 mm or 0.8 mm, and/or a restoring force of more than 20 N in case of an elastic elongation of at least 0.8 mm or 0.9 mm, a restoring force of at least 20 N or 25 N in case of an elastic elongation of at least 1.0 mm or 1.1 mm.

7. A liquid dosing device (1) according to claim 1, wherein the sealing lip (59) forms a sealing surface facing the seat-sided portion of the floating plunger (39) or the plunger-sided portion of said slop seat (55), said sealing surface being formed convexly, particularly the sealing lip (59) comprising a surface opposite the sealing surface being formed convexly.

8. A liquid dosing device (1) according to claim 1, wherein said sealing lip (59) has a rotationally symmetrical shape, particularly being fantail-shaped or being cup-shaped, particularly having a central orifice.

9. A liquid dosing device (1) according to claim 1, wherein said stop seat (55) is realized by a tube portion (67) forming at least part of the outlet passage (16), wherein particularly said tube portion (67) is part of a mounting ring comprising an attachment portion (57) for being attachable to a cover cap (5) covering the discharge opening (17), wherein preferably the attachment portion (57), the tube portion (67) and the sealing lip (59) is unitarily manufactured of one single piece of the same plastic material, wherein particularly said mounting ring is designed to fix a blocking valve (21) disposed in the outlet passage (16) and made of an elastic material, as an elastomeric material, being softer than the plastic material of said sealing lip (59), to said cap (5).

10. A liquid dosing device (1) according to claim 9, wherein said blocking valve (21) is arranged between said discharge opening (17) and said at least one charge opening (19) in front of the dosing chamber (11).

11. A liquid dosing device (1) according to claim 1, characterized in that the floating plunger (39) comprising a carrier portion (69) forming the seat-sided portion and holding said sealing lip (59), wherein particularly said carrier portion (69) and the sealing lip (59) is manufactured, particularly injection-mold of one single piece of plastic, wherein particularly said floating plunger (39) comprises a closed cavity partially confined by said carrier portion (69).

12. A liquid dosing device (1) according to claim 1, wherein said floating plunger (39) comprises a contact surface facing the sealing lip (59) unitarily formed with said plunger-sided portion of the stop seat (55), and is recessed such that an annular, particularly circular sealing end (60) of said sealing lip (59) is received in the recess in the blocking position, wherein particularly said recess is formed as a blind hole in the body of said floating plunger (39).

Description

[0054] Further advantages, features and characteristics of the invention become obvious from the following description of preferred embodiments of the invention, shown in the enclosed drawings according to which

[0055] FIG. 1 is a diagram showing the elastic elongation of the sealing lip/displacement of the floating plunger with respect to the force of pressure applied to the sealing lip, according to a preferred embodiment of the invention;

[0056] FIG. 2 is a cross section of the liquid dosing device according to a first embodiment of the invention, the cross section being taken along the section line II-II according to FIG. 3;

[0057] FIG. 3 is a top view of the liquid dosing device according to FIG. 2;

[0058] FIG. 4 is a perspective view of the liquid dosing device according to FIG. 2 or 3;

[0059] FIG. 5 is a cross section of a clamp ring inserted in the liquid dosing device according to FIGS. 2 to 4, the section being taken along the section line V-V of FIG. 7;

[0060] FIG. 6 is a side view of the clamp ring according to FIG. 5;

[0061] FIG. 7 is a top view of the clamp ring according to FIGS. 5 and 6;

[0062] FIG. 8 is a perspective view the clamp ring according to FIGS. 5 to 7;

[0063] FIG. 9 is a cross section of the liquid dosing device according to a second embodiment of the invention, the cross section being taken along the section line IX-IX according to FIG. 10;

[0064] FIG. 10 is a top view of the liquid dosing device according to FIG. 9;

[0065] FIG. 11 is a perspective view of the liquid dosing device according FIGS. 9 and 10;

[0066] FIG. 12 is a cross section of the floating plunger of the liquid dosing device according to a second embodiment of the invention.

[0067] FIG. 13 is a side view on the floating plunger according to FIG. 12;

[0068] FIG. 14 is a top view of the floating plunger according to FIGS. 12 and 13; and

[0069] FIG. 15 is a perspective view of the floating plunger according to a second embodiment;

[0070] FIGS. 16a to 16c is a cross sectional view of the liquid dosing device according to the invention and three different operation conditions;

[0071] FIG. 17 is a cross section of the liquid dosing device according to the invention according to a second embodiment;

[0072] FIG. 18 is a perspective view of the liquid dosing device realized in form of a cap with an outside hinged lid in an open condition;

[0073] FIG. 19 is a side view on the liquid dosing device according to FIG. 18; and

[0074] FIG. 20 is a top view of the liquid dosing device according to FIGS. 18 and 19.

[0075] In FIGS. 2 to 4 and 9 to 11, a liquid dosing device is generally associated to reference sign 1. The liquid dosing device 1 comprises a base 3 having an inner thread 8 for fixing the liquid dosing device 1 to a squeezable liquid carrying container (not shown). Further, the liquid dosing device 1 comprises a cap 5 which is hinged to the base 3 having an axially extending nose 4 for closing an outlet passage 16 particularly a discharge opening 17 of the outlet passage 16. In FIGS. 3, 4, 10 and 11, a liquid dosing device 1 is shown including details of the outside. The base 3 has a serrated surface and is to be mounted on said container (not shown).

[0076] The liquid dosing device 1, according to FIGS. 2 and 9, in general comprises a cylindrical body 7 having an essentially cylindrical sidewall 9 that extends concentrically relative to a rotational axis A of the base 3, cap 5 and/or device 1. The cylindrical body 7 forms a dosing chamber 11 defining a dosing and driving volume. The dosing chamber 11 is separated into two compartments 12, 14 the volume of which depends on an axial position of an axially movable floating plunger 39 guided by the cylindrical sidewall 9 of the cylindrical body 7. The rear compartment 12 is confined by a horizontal base plate 13 of the cylindrical body 7 and the rear portion of the floating plunger 39. The front compartment 14 is open to the outlet passage 10 and is confined by the front portion of the floating plunger 39 and the cylindrical sidewall 9, however, as soon as the floating plunger 39 gets in contact with an element of a stop seat 55 the front compartment 14 is sealingly closed. The structure for closing the front compartment 14 will be explained in detail later.

[0077] The cylindrical body 7 forming the dosing chamber 11 is fixedly connected to the base 3 by means of a geometric clamping structure 29. The cylindrical body 7 particularly the base plate 13 comprises a drive opening 15 formed as a throughhole in the base plate 13 centrically relative to the axis A. On the opposite side of the base plate 13, which faces the outlet passage 16, the discharge outlet or opening 17 is formed in base 3.

[0078] The cylindrical sidewall 9 of the dosing chamber 11 comprises at its front section at least one, exactly two, three or four charge openings 19 defined by cutouts preferably equally sized and circumferentially equally distributed around the cylindrical sidewall 9 essentially on the same axial level.

[0079] A blocking valve 21 is installed between the dosing chamber 11 and the discharge opening 17. The elastomeric blocking valve 21 comprises a valve closure member 23 that is bendable relative to an anchor ring 25 fixed to the base 3 to open and close a throughway from the dosing chamber 11 to the discharge opening 17. Particularly regarding the structure and the functioning of the blocking valve 21, it is referred to the technical content of the earlier European patent application EP 14 003 059.4. The blocking valve 21 comprises a valve closure element 23 which is realized by a thin walled, dome shaped element partly like a membrane. The blocking valve 21 is made from a silicon elastomer and is glued or clamped sealingly within an interior circumference of the base 3. The silicon membrane is slotted in an X-like fashion to define four elastic snap-over flaps 63, 65. The snap-over flaps 63, 65 decrease in thickness from radially outward to radially inwards to provide a bending stiffness gradient adjusted with respect to the pressure gradient within the dosing chamber 11, when the container is squeezed.

[0080] The dosing chamber 11 comprises a mounting rim 29 which is slidably received within a complementary installment groove 31 formed by base 3. The mounting rim 29 is axially fixed by a snap tap 33 extending radially from the base 3 at the installment groove 31. The base 3 defines several ring-shaped rims extending axially towards the dosing chamber 11. The installment groove 31 is defined between two of these rims. The base 3 comprises a further, particularly concentrically most inner rim 35, which defines the outlet passage 16. The blocking valve 21 is mounted by the inner rim 35 and by a clamp ring 71 clamping an annular clamp lip of the blocking valve 21 against the inner rim 35. Further, the clamp ring 71 is snap fitted within an inner installment groove defined by the most inner rim 35 and an intermediate rim also comprising an annular snap tap.

[0081] The sidewall 9 is made by a hard plastic material, as polypropylene or polyethylene, particulary to reduce adhesion forces with the floating plunger 39, which is vertically slidable within the dosing chamber 11, and allow fast reversal of the floating plunger 39 because of buoyancy forces acting on the floating plunger 39 submerged in the liquid, when the squeezing pressure is released. The floating plunger 39 has a downstream or front rim 41, providing a first effective sliding element with the cylindrical sidewall 9 and facing the discharge opening 17, and an upstream or rear rim 43, providing a second effective sliding element facing the drive opening 15. The upstream and downstream rims 41, 43 have the same maximum diameter being essentially equal to the inner diameter of the dosing chamber 11. The rims 41, 43 are circular and disc-shaped complementarily relative to the cylindrical sidewall 9 of the dosing chamber 11.

[0082] The floating plunger 39 is formed by two cross-sectional U-shaped thinwalled bushing elements 45, 47 connected to each other in a telescopically slidable manner. By clamping the annular legs of the cross-sectional U-shaped bushing elements 45, 47, both bushing elements 45, 47 are releasably fixed to each other. The bushing elements 45, 47 define an essentially cylindrical interior volume of the plunger 39. The volume is adaptable by either telescopically displacing one bushing 45, 47 from the other or by changing the diameter of the interconnecting cylindrical body portions 49, 51 of the bushings 45, 47. The size of the volume can be adjusted in order to change the buoyancy characteristics of the floating plunger 39 submerged in the liquid. The container is in a position upright that means that the liquid dosing device 1 is positioned according to FIGS. 2 and 9. However, for immediate dosing, the container should be positioned upside down so that the liquid dosing device 1 faces downwards (not shown in the drawings). As the upstream and the downstream rims 41, 43 each extend radially beyond the cylindrical body portions 49, 51, respectively, an annulus-shaped chamber 53 is formed between the rims 41, 43, the outer surface of the body portions 49, 51 and the cylindrical side wall 9.

[0083] In an initial operative condition of the liquid dosing device 1, starting the use of the liquid dosing device 1, no liquid pressure apart from atmospheric pressure is present. Liquid stored in the container enters the front compartment 14 of the dosing chamber 11 under the influence of gravity via charge opening 19. When the front compartment 14 is completely filled, the floating plunger 39 (against its gravity) due to buoyancy force is pushed upwards and towards the base plate 13 of the dosing chamber 11. As soon as the floating plunger 39 is in contact with the base plate 13 the dosing volume within the front compartment 14 is complete and maximal. As soon as a squeezing force is applied to the container the liquid pressure in the container is increased. Said liquid pressure acts on the rear disc of the floating plunger 39 via the drive opening 15. At the same time the pressure liquid in the dosing chamber 11 and the pressure on the closure element 23 of the blocking valve 21 increases. The closure element 23 of the blocking valve 21 is adapted to resist a predetermined pressure threshold before opening a passageway for the liquid through the blocking valve 21. As soon as the squeezing pressure acting on the valve closure element 23 exceeds the blocking valve threshold, the blocking valve 21 opens, thereby decreasing the pressure within the dosing chamber 11. The pressure gradient resulting from high squeezing pressure acting on the rear disc of the floating plunger 39 and the decreasing pressure within the dosing chamber 11 (the front compartment 14) causes the floating plunger 39 to move from its rest position (not shown) into a blocking position shown in FIGS. 2 and 9. The floating plunger 39 pushes the liquid stored within the front compartment 14 of the dosing chamber 11 through valve slits 27 and the discharge opening 17.

[0084] Referring to FIGS. 2 and 9, the liquid dosing device 1 is shown in an operating condition, in which the floating plunger 39 has arrived at its blocking position. The complete content of the front compartment 14 of the dosing chamber 11 has been drained through the valve opening 27 to the discharge opening 17.

[0085] If the squeezing pressure on the container is released, suction forces generated by reformation of the deformed container will reverse the pressure gradient, so that any liquid remaining at the valve closure member 23 is sucked back into the dosing chamber 11. The pressure acting on the upstream rim 43 of the floating plunger 39 is reversed so that the floating plunger 39 begins to uncover the charge openings 19. Liquid remaining in the dosing chamber 11 exerts buoyancy forces on the floating plunger 39. As soon as the charge openings 19 are partially opened, liquid streams back into the dosing chamber 11. The floating plunger 39 and its interior volume are dimensioned and adapted such that the buoyance force acting on the floating plunger 39 due to the liquid streaming into the dosing chamber 11 lifts the floating plunger 39 back into its rest position.

[0086] Taking a further look to the blocking position of the floating plunger it shall be clear that the floating plunger 39 will get in contact with a sealing lip 59, however, in any blocking position will not get in contact with the blocking valve 21. Therefore, the sealing lip 59 must have an elasticity and a rigidity in that for each theoretical and practical use conditions, a contact of the floating plunger 39 (i.e. the sealing lip 59) with the blocking valve 21 should be excluded in the blocking position.

[0087] To provide a reliable sealing of the dosing device 1, even if a high squeezing pressure is generated, a sealing lip 59 is provided either at the stop seat 55 or at the floating plunger 39 in order to shut-off the fluidal connection between the front compartment 14 and the outlet passage 16. Alternative solutions are shown in FIGS. 2 to 8 and 9 to 15, respectively.

[0088] In a first preferred embodiment of the invention according to FIGS. 2 to 8, the stop seat 55 is unitarily formed with the annular sealing lip 59. The stop seat 55 comprises an axially extending annular attachment portion 57, which is clamped between two axially extending annular rims of the dosing device 1 retaining the clamping lip 37 of the blocking valve 21, a tube portion 67 and the sealing lip 59, which sealingly engages in the blocking position with the floating plunger 39. The tube portion 67, the attachment portion 57 and the sealing lip 59 are injection-mold, of one single piece of same plastic material, like polypropylene, polyethylene or the like.

[0089] The sealing lip 59 extends by about 2 mm to 3 mm from a plunger-sided portion of the tube position 67. The sealing lip 59 comprises a lip body 54 comprising an annular foot portion 58, which merges with the plunger-sided portion of the tube portion 67, and an annular sealing end 60, which forms a circumferentially closed sealing contact with the floating plunger 39. The sealing lip 59 is formed such that it is elastically deformable and has an elastic elongation in an axial direction, particularly defined by the axial extension of the outlet passage 16. Therefore, unevenness of the material itself can be compensated because the contact pressure between the floating plunger 39 and the sealing lip 59 leads to an elastic deformation and particularly to a clinging effect of the lip 59, whereby a reliable and strong sealing ability is provided. As can be seen, the sealing lip 59 radially extends, wherein along said extension, the cross-section of the sealing lip 59 continuously reduces to ensure the elastic deformation. The plunger-sided surface of the sealing lip 59 is formed convexly. The opposite surface of the sealing lip 59 is concavely shaped. The sealing lip comprises a cup-shape or fantail-shape including a centered throughhole 61.

[0090] According to the embodiment of FIG. 2, the floating plunger 39 comprises a contact surface facing the sealing lip 59 unitarily formed with the plunger-sided portion of the stop seat 55. The disc-like front end of the floating plunger 39 is recessed for forming a blind hole recess 73. The bottom of said recess 73 comes into seal engagement with the sealing lip 59 in the blocking position of the floating plunger 39. Particularly, the sealing lip 59 extends from the plunger-sided portion of the stop seat 55 radially inwardly towards the plunger 39. Said bottom of the recess 73 is made of hard plastic material, particularly same material as the sealing lip 59.

[0091] Referring to FIGS. 5 to 8, a top view, a side view, a cross-sectional view and a perspective view of the stop seat 55 including the unitary sealing lip 59 of FIG. 2 are shown. The stop seat 55 is formed as a rotational symmetrical dome with the throughhole 61 in the center, particularly concentrically arranged with respect to axis A. A groove 56 is provided on an outer surface of the stop seat 55 to determine the circumferential position of the stop seat 55 to be mounted in the liquid dosing device 1.

[0092] The second embodiment of the invention is described in view of FIGS. 9 to 15, however, for a better understanding of the description of figures, for the same elements and structures of the liquid dosing device, particularly the floating plunger 39, the stop seat 55 and the sealing lip 59, of FIGS. 9 to 15 the same reference signs are used as in the drawings of the embodiment according to FIGS. 2 to 8.

[0093] The embodiment of the liquid dosing device 1 according to FIGS. 9 to 15 differentiates from the first embodiment particularly by the structure of the floating plunger 39 and the stop seat 55. The sealing lip 59 and the floating plunger 39 are manufactured, particularly injection-mold, of one single piece of same plastic material, as polyethylene, polypropylene or the like. The floating plunger 39 comprises a disc-like carrier portion 69 forming a seat-sided portion and holding the sealing lip 59. The fantail-shaped axially and radially extending sealing lip 59 is formed adjacent the front rim 41 of the floating plunger 39 and extends radially outwardly towards the stop seat 55.

[0094] For both embodiments, in order to be elastically deformable and to provide the improved sealing function, the sealing lip 59 comprises a cross-section which continuously reduces from its foot portion 58 up to the sealing end 60.

[0095] Referring to FIGS. 12 to 15, a top view, a side view, a cross-sectional view and a perspective view of the floating plunger 39 according to the second embodiment are shown. As can be seen in FIG. 12, the sealing lip 59 comprises a fantail-shape, having a convexly formed surface facing to the stop seat 55. The opposite surface of the sealing lip 59 is concavely shaped.

[0096] In FIG. 1, the influence of an axial elastic deformation of the sealing lip 59 of the stop seat 55 on the axial restoring force produced by the sealing lip 59 onto the floating plunger 39 is illustrated by the graphical gradient g for a result of measurements regarding a preferred embodiment of the liquid dosing device 1. When the floating plunger 39 presses on the stop seat 55 to block the liquid from entering the outlet passage 16, the sealing lip 59 experiences an elastic axial deformation, which corresponds to an axial shifting of the floating plunger 39 of up to 1.0 mm or 1.5 mm. The elastic elongation can be measured by a displacement between the axial position of the floating plunger 39 when it just contacts the sealing lip 59 and the axially displaced position when a pressure force is applied to the sealing lip 59. By the deformation of the sealing lip 59, the last applies axial elastic restoring force acting on the floating plunger 39. Said axial elastic restoring force can be measured by conventional load cells which are arranged at the upstream or rear end of the floating plunger 39. It shall be clear that those measurements shall be undertaken without the application of liquid, rather in a dry condition in the presence of standard environmental conditions.

[0097] It turned out that the gradient shown in graphical FIG. 1 represents a measuring result of a preferred embodiment of the invention. In a case of a 0.2 mm elastic elongation of the sealing lip, an elastic axial restoring force of about 2 N can be sensed. For an elastic elongation of 0.3 mm, an elastic axial restoring force of 4 N was measured, etc. It turned out that by the respective sealing lip geometry, an elastic deformation of the sealing lip 59 of up to 1.0 mm can be realized, on one hand-side tightly closing the outlet passage 16, on the other hand, a precise dosage volume can be maintained and easily predicted.

[0098] A further embodiment of a liquid dosing device 101 according to the invention is shown in FIGS. 16a to 16c. The liquid dosing device 101 is fixed to a threaded base 111 of a cap 110 which is to be installed on a liquid carrying container (not shown). The liquid dosing device 110 comprises a hollow body 4 having an essentially hollow cylindrical sidewall 103 that extends concentrically relative to the threaded base 111 of the cap. The dosing chamber is closed by a base plate 103′ on the side that faces the interior of the container. A drive opening 108 is formed as a through hole in the base plate 103′ centrically relative to the hollow body 104 and/or the cap base 011. On the opposite side of the base plate 103′, which faces the outside of the container, a discharge outlet 105 is formed as one piece with the threaded base 111. The interior of the hollow body 104 forms a dosing chamber 107.

[0099] The cylindrical sidewall 103 of the dosing chamber 107 comprises four charge openings 109, 109′ defined by cutouts, which are of equal size and circumferentially equally distributed around the cylindrical sidewall 103.

[0100] A blocking valve 150 is installed between the dosing chamber 107 and the discharge outlet 105. The blocking valve 150 comprises a valve closure member 152 that is bendable relative to an anchor ring fixed to the cap base 111 to open and close a throughway or aperture 151 from the dosing chamber 107 to the discharge outlet 105.

[0101] The dosing chamber 107 comprises a mounting rim 121 which is slidably received within a complementary installment groove 123 formed by the threaded base 111 of the cap 110 and held by a snap tap 125 extending concentrically on the radially outer side from the installment groove 123. The base 111 of the cap defines several ring shaped rims extending axially towards the dosing chamber. The installment groove 123 is defined between two of these rims. The base 111 comprises a further, particularly concentrically most inner rim, which defines the discharge outlet 105. The blocking valve 150 is mounted on the inner rim via a base lip 159 resting on the inner rim. A clamp ring 122 keeps the base lip of the blocking valve 150 into position. The clamp ring 122 is hold by a lug structure formed on a concentrically adjacent rim of the base 111. The clamp ring 122 extends from the discharge outlet 105 into the dosing chamber 107 beyond the blocking valve 150 to form an abutment for the floating plunger 106 in its blocking position. The clamp ring 122 is made by hard plastic to reduce adhesion forces with the floating plunger 106 and allow fast reversal of the floating plunger 6, when the squeezing pressure is released.

[0102] A floating plunger 106 is slidably mounted within the dosing chamber 107. The floating plunger 106 has a downstream rim 165, providing a first effective surface, facing the discharge outlet 105 and an upstream rim 167, providing a second effective, side, facing the drive opening 108. The upstream and downstream rims 165, 167 have the same maximum diameter being essentially equal to the inner diameter of the dosing chamber 107. While the down-stream rim 165 is circular or disc shaped, the upstream rim 167 has a quadratic effective surface with edged rounded complementary relative to the cylindrical sidewall 103 of the dosing chamber 107.

[0103] The floating plunger 106 is formed by two mushroom- or double-T-shaped thinwalled bushing elements 161, 163 connected to each other in a telescopically slidable manner. The bushing elements 161, 163 define an essentially cylindrical interior volume of the plunger. The volume is adaptable by either telescopically displacing one bushing 161, 163 from the other or by changing the diameter of the interconnecting cylindrical body portions 162, 164 of the bushings 161, 163. As the upstream and the downstream rims 165, 167 each extend radially beyond the cylindrical body portions 162, 164, respectively, an annulus-shaped chamber 169 is formed between the rims 165, 167, the outer surface of the body portions 162, 164 and the cylindrical side wall 103.

[0104] Referring to FIG. 1a, the liquid dosing device 101 is shown in its initial condition in which no liquid pressure apart from atmospheric pressure and the influence of gravity on the liquid is exerted on the floating plunger 106 and blocking valve 150. Liquid stored in the container enters the dosing chamber 107 under the influence of gravity via charge openings 108. As soon as a squeezing force is applied to the container the pressure in the container is increased thereby, the pressure that acts on the upstream rim 167 of the floating plunger 106 via the drive opening 108 increases. At the same time the pressure on the liquid in the dosing chamber 107 and the pressure on the closure element 152 of the blocking valve 150 increases.

[0105] The closure element 152 of the blocking valve is adapted to resist a predetermined pressure threshold before opening a passageway for the liquid through the blocking valve 150.

[0106] As soon as the squeezing pressure acting on the valve closure element 152 exceeds the blocking valve threshold, the valve 150 opens, thereby decreasing the pressure within the dosing chamber 107. The pressure gradient resulting from high squeezing pressure acting on the upstream rim 167 of the floating plunger 106 and the decreasing pressure within the dosing chamber 107 causes the floating plunger 106 to move from its initial position shown in FIG. 1a towards the blocking valve 150 and the discharge outlet 105. The moving plunger 106 pushes the liquid stored within the dosing chamber through the valve aperture or opening 151 and the discharge outlet 105. As the squeezing pressure is higher than the pressure within the dosing chamber 107 owing to the blocking valve being open, no liquid flows back into the container through the charge openings 109, 109′ but through the discharge outlet 105.

[0107] An intermediate condition, in which the floating plunger 106 is on its way from the initial position towards a blocking position, is represented by FIG. 16b. Though not explicitly shown in FIG. 16b, it should be clear that the valve is opened in this operating condition.

[0108] Referring to FIG. 16c, the liquid dosing device 101 is shown in an operating condition, in which the floating plunger 106 has arrived at its blocking position. The complete content of the dosing chamber 107 has been drained through the valve opening 151 and the discharge outlet 105. As soon as a floating plunger 106 reaches the blocking position, the downstream rim 165 closes the valve 150 and the discharge outlet 105 from its upstream side by abutting the clamp ring 122, so that liquid is blocked from leaving the valve opening 151. The abutment between the floating plunger 106 and the clamp ring 122 suffices to avoid emission of any further liquid to the blocking valve 150. The floating plunger 106 further blocks the entry of liquid through the charge openings 109, 109′ in the dosing chamber 107 or towards to the blocking valve 150, so that no liquid beyond the metered dose within the dosing chamber 107 can flow out of the discharge outlet 105.

[0109] If the squeezing pressure on the container is released, suction forces generated by reformation of the deformed container will reverse the pressure gradient, so that any liquid remaining at the valve closure member 152 is sucked back into the dosing chamber 107. The pressure acting on the upstream rim 167 of the floating plunger 106 is reversed so that the plunger begins to uncover the charge openings 109, 109′. Liquid remaining in the annulus chamber 169 may exert some initial buoyancy force on the floating plunger 106. As soon as the charge openings 109, 109′ are partially opened, liquid streams back into the dosing chamber 107. The floating plunger 106 and its interior volume are dimensioned and adapted such that the buoyance force acting on the floating plunger 106 due to the liquid streaming into the dosing chamber 107 lifts the floating plunger 106 back into its initial position, shown in FIG. 16a.

[0110] Referring to FIG. 19, a second embodiment of the liquid dosing device 201 according to the invention is shown. The device as shown is suitable for pasty or viscous liquids that provide a high surface tension so as to function as a blocking valve if contained in the dosing chamber 7 of the device 201. In this specific embodiment, no particular blocking valve is shown but the diameter of the discharge outlet 105 may be adapted to provide together with the viscous consistency of specific liquids a certain pressure threshold before liquid leaves in the outlet 105 The working principle of this second embodiment is similar to the working principle of the first embodiment according to FIGS. 16a to 16c. However, the pressure threshold is not provided by a flexible valve closure element 152 but by the liquid itself. As soon as the squeezing pressure overcomes a pressure threshold necessary to overcome a surface tension at the discharge outlet 105, the pasty liquid is discharged and a pressure gradient results between the dosing chamber 7 and the remaining container. The further course of operation is equal to the course of operation as described with respect to the first embodiment and FIGS. 16a to 16c.

[0111] Referring to FIGS. 18, 19 and 20, a liquid dosing device 101 according to the first embodiment is shown in connection with a container cap 110. The container cap 110 comprises a base portion 111 with a serrated outside to be mounted on a container. A lid 113 is hingedly connected to the base 111 of the cap 10. As can be seen best in FIG. 19, the cylindrical sidewall 103 of the liquid dosing device 101, 201 extends axially towards the interior of the container. Some details regarding the blocking valve 150 are best seen in FIG. 20. The blocking valve 105 comprises a valve closure element 151 which is realized by an elastic thin walled dome shaped element like a membrane. The membrane is made from a silicon elastomer and is glued or clamped sealingly within an interior circumference of the discharge outlet 105. The silicon membrane is slotted in an X-like fashion to define four elastic snap-over flaps 153, 153′. The snap-over flaps 153, 153′ decrease in thickness from radially outward to radially inwards to provide a bending stiffness gradient adjusted with respect to the pressure gradient within the dosing chamber 107, when the container is squeezed.

[0112] The features disclosed in the above description, the figures and the claims can be significant for the realization of the invention in the different embodiments either alone or in combination.

LIST OF REFERENCE SIGNS

[0113] 1 liquid dosing device

[0114] 3 base

[0115] 5 cap

[0116] 6 nose

[0117] 7 hollow body

[0118] 8 thread

[0119] 9 cylindrical sidewall

[0120] 11 dosing chamber

[0121] 12 rear compartment

[0122] 13 base plate

[0123] 14 front compartment

[0124] 15 drive opening

[0125] 16 outlet passage

[0126] 17 discharge opening

[0127] 19 charge openings

[0128] 21 blocking valve

[0129] 23 closure element

[0130] 25 anchor ring

[0131] 27 slit or opening

[0132] 29 mounting rim

[0133] 31 installment groove

[0134] 33 snap tap

[0135] 35 inner rim

[0136] 37 base lip

[0137] 39 floating plunger

[0138] 41 downstream rim

[0139] 43 upstream rim

[0140] 45, 47 bushing elements

[0141] 49, 51 body portions

[0142] 53 annulus chamber

[0143] 54 lip body

[0144] 55 stop seat

[0145] 56 groove

[0146] 57 attachment portion

[0147] 58 foot portion

[0148] 59 sealing lip

[0149] 60 sealing end

[0150] 61 center throughhole

[0151] 63, 65 snap-over flaps

[0152] 67 tube portion

[0153] 69 carrier portion

[0154] 71 clamp ring

[0155] 73 sealing edge

[0156] A rotational axis

[0157] g gradient

[0158] 101, 201 liquid dosing device

[0159] 103 sidewall

[0160] 103′ base plate

[0161] 104 hollow body

[0162] 105 discharge outlet

[0163] 106 floating plunger

[0164] 107 dosing chamber

[0165] 108 drive opening

[0166] 109, 109′ charge opening

[0167] 110 cap

[0168] 111 base

[0169] 113 lid

[0170] 121 mounting rim

[0171] 122 clamp ring

[0172] 123 groove

[0173] 125 snap tap

[0174] 150 blocking valve

[0175] 151 aperture

[0176] 152 valve closure member

[0177] 159 clamp lip

[0178] 153, 153′ flaps

[0179] 161,163 bushing elements

[0180] 162,164 body portions

[0181] 165 downstream rim

[0182] 167 upstream rim

[0183] 169 chamber