US-20260124630-A1 - PUMP MODULE, DISCHARGE HEAD AND FLUID DISPENSER

Abstract

A pump module comprising a pump cylinder having a fluid inlet, an inlet valve, a stem and a piston attached to the stem and within the pump cylinder and defining a pump chamber together with the pump cylinder, the stem extending out of the pump cylinder and comprising an outlet channel. The pump module comprises a return spring wherein the stem and the piston are pressed in the direction of the unactuated end position, the return spring. A ventilation path through which an interior space of the return spring is connected to a surrounding atmosphere runs at least partially through at least one ventilation aperture or at least one end-side recess in the return spring and/or through at least one ventilation channel or at least one ventilation groove in the support collar attached to the pump cylinder.

Inventors

• Karlheinz Hummel
• Peter Suess
• Olivier Lecomte
• Stéphane GATIER

Assignees

• APTAR VILLINGEN GMBH

Dates

Publication Date

20260507

Application Date

20230829

Priority Date

20220831

Claims (20)

1. 1 . A pump module for a liquid dispenser, the pump module comprising: a pump cylinder having a fluid inlet at one end and an inlet valve; a stem and a piston attached to the stem, the piston being located within the pump cylinder and defining a pump chamber together with the pump cylinder, the stem extending out of the pump cylinder and comprising an outlet channel of the pump module, the stem and the piston being movable relative to the pump cylinder from an unactuated end position with a maximum volume of the pump chamber to an actuated end position with a minimum volume of the pump chamber in order to press fluid out of the pump chamber into the outlet channel; a return spring in the form of a bellows spring or a dome-shaped spring by which return spring the stem and the piston are pressed in the direction of the unactuated end position, the bellows spring or the dome-shaped spring being supported with a first end surface by the stem or a support collar fixedly attached to the stem and being supported with a second end surface by the pump cylinder or a support collar fixedly attached to the pump cylinder; and a ventilation path, through which ventilation path an interior space of the bellows spring or the dome-shaped spring is connected to a surrounding atmosphere, said ventilation path running at least partially through at least one ventilation aperture or at least one end-side recess in the bellows spring or the dome-shaped spring and/or through at least one ventilation channel or at least one ventilation groove in the support collar attached to the pump cylinder.
2. 2 . The pump module according to claim 1 , wherein the return spring comprises the bellows spring and the bellows spring comprises a bellows part, the bellows spring including a helical fold protrusion or a plurality of annular fold protrusions that allow a length of the bellows part to be changed when the bellows spring is compressed.
3. 3 . The pump module according to claim 1 , wherein at least one end of the bellows spring or the dome-shaped spring has an annular interrupted end surface, the interrupted end surface being interrupted by at least one recess to form the ventilation path.
4. 4 . The pump module according to claim 3 , wherein the pump module comprises a support surface for supporting the interrupted end surface, the support surface comprises an outer retaining wall, the outer retaining wall preventing or limiting radial expansion of the bellows spring or the dome-shaped spring in a region of the support surface.
5. 5 . The pump module according to claim 2 , wherein at least one end of the bellows spring has an annular interrupted end surface, the interrupted end surface being interrupted by at least one recess to form the ventilation path, the pump module comprises a support surface for supporting the interrupted end surface, and the support surface is provided on a support collar attached to the pump cylinder.
6. 6 . The pump module according to claim 3 , wherein a cross section of the at least one recess tapers from an inner side of the bellows spring to an outer side of the bellows spring.
7. 7 . The pump module according to claim 1 , wherein the bellows spring or the dome-shaped spring has at least one ventilation aperture circumferentially surrounded by material of the bellows spring or the dome-shaped spring.
8. 8 . The pump module according to claim 7 , further comprising a plurality of ventilation apertures in the bellows spring or the dome-shaped spring, the ventilation apertures having parallel directions of extension.
9. 9 . The module according to claim 1 , wherein at least one and the bellows spring or the dome-shaped spring has an annular interrupted end surface, the interrupted end surface being interrupted by at least one recess to form the ventilation path, the bellows spring or the dome-shaped spring having at one end an inwardly pointing demolding rim provided at an end opposite the interrupted end surface.
10. 10 . The pump module according to claim 1 , wherein the support collar on the pump cylinder has a support surface on an upper side for support of the bellows spring, the support collar has at least one groove in a contact surface forming a part of the ventilation path, wherein in a region of said groove an end surface of the bellows spring does not bear against the support collar.
11. 11 . The pump module according to claim 10 , wherein the support surface comprises an outer retaining wall for holding a lower end collar of the bellows spring or the dome-shaped spring in a region of the support surface, and the at least one groove penetrates the outer retaining wall.
12. 12 . The pump module according to claim 11 , wherein the outer retaining wall comprises an internal inlet slope for inserting the lower end collar of the bellows spring or the dome-shaped spring.
13. 13 . The pump module according to claim 11 , wherein the outer retaining wall is configured as a circumferential wall, the circumferential wall only being interrupted in an area of the at least one groove, and the at least one groove spans a maximum of 20% of a wall circumference of the outer retaining wall.
14. 14 . The pump module according to claim 11 , wherein the lower end collar is in circumferential contact with an inner side of the outer retaining wall except in a region of the at least one groove.
15. 15 . The pump module according to claim 1 , wherein at least one ventilation channel penetrates the support collar.
16. 16 . The pump module according to claim 1 , wherein the piston is movable in a limited way relative to the stem, the piston and the stem together form an outlet valve which can be opened and closed by relative movement of the piston relative to the stem.
17. 17 . A discharge head for a liquid dispenser, comprising a base for attachment to a liquid reservoir; an applicator unit having a discharge opening, said applicator unit being displaceable relative to the base in a pumping movement; and the pump module comprising: a pump cylinder having a fluid inlet at one end and an inlet valve; a stem and a piston attached to the stem, the piston being located within the pump cylinder and defining a pump chamber together with the pump cylinder, the stem eztending out of the pump cylinder and comprising an outlet channel of the pump module, the stem and the piston being movable relative to the pump cylinder from an unactuated end position with a maximum volume of the pump chamber to an actuated end position with a minimum volume of the pump chamber in order to press fluid out of the pump chamber into the outlet channel; a return spring in the form of a bellows spring or a dome-shaped spring by which return spring the stem and the piston are pressed in the direction of the unactuated end position, the bellows spring or the dome-shaped spring being supported with a first end surface by the stem of a support collar fixedly attached to the stem and being supported with a second end surface by the pump cylinder or a support collar fixedly attached to the pump cylinder; and a ventilation path, through which ventilation path an interior space of the bellows spring of the dome-shaped spring is connected to a surrounding atmosphere, said ventilation path running at least partially through at least one ventilation aperture or at least one end-side recess in the bellows spring or the dome-shaped spring and/or through at least one ventilation channel or at least one ventilation groove in the support collar attached to the pump cylinder.
18. 18 . A fluid dispenser for dispensing a fluid product, the fluid dispenser comprising: a fluid reservoir; and a discharge head comprising a pump module, the pump module comprising: a pump cylinder having a fluid inlet at one end and an inlet valve; a stem and a piston attached to the stem, the piston being located within the pump cylinder and defining a pump chamber together with the pump cylinder, the stem extending out of the pump cylinder and comprising an outlet channel of the pump module, the stem and the piston being movable relative to the pump cylinder from an unactuated end position with a maximum volume of the pump chamber to an actuated end position with a minimum volume of the pump chamber in order to press fluid out of the pump chamber into the outlet channel; a return spring in the form of a bellows spring of a dome-shaped spring by which return spring the stem and the piston are pressed in the direction of the unactuated end position, the bellows spring or the dome-shaped spring being supported with a first end surface by the stem or a support collar fixedly attached to the stem and being supported with a second and surface by the pump cylinder or a support collar fixedly attached to the pump cylinder; and a ventilation path, through which ventilation path an interior space of the bellows spring or the dome-shaped spring is connected to a surrounding atmosphere, said ventilation path running at least partially through at least one ventilation aperture or at least one end-side recess in the bellows spring or the dome-shaped spring and/or through at least one ventilation channel or at least one ventilation groove in the support collar attached to the pump cylinder.
19. 19 . The pump module according to claim 3 , wherein: the bellows spring or the dome-shaped spring has a plurality of recesses interrupting the interrupted end surface; and/or the interrupted end surface is interrupted by the at least one recess to a maximum of 30% of its circumference; and/or the bellows spring has a bellows collar at an end on which the interrupted end surface is provided, the bellows collar having a wall thickness larger than a wall thickness of a bellows part of the bellows spring, the wall thickness of the bellows collar being twice as large than the wall thickness in the bellows part.
20. 20 . The pump module according to claim 7 , wherein: the bellows spring or the dome-shaped spring has a plurality of ventilation apertures; and/or the at least one ventilation aperture is provided in a bellows part of the bellows spring; or the at least one ventilation aperture is provided in a bellows collar of the bellows spring at one end of the bellows spring.

Description

FIELD OF APPLICATION AND STATE OF THE ART The invention relates to a pump module for usage as part of a fluid dispenser as well as to a discharge head and a fluid dispenser containing such a pump module. A pump module according to the invention is being used for example in fluid dispensers for skin lotions as well as in fluid dispensers for other cosmetic products or pharmaceutical liquids. Pump modules of this type are intended to be combined with a liquid reservoir. A pump stem with a piston is movable in a pump cylinder of the pump module. An applicator unit is attached to the stem, said applicator unit having a discharge opening. When the applicator unit is pressed down, the stem and a piston attached thereto are pressed into a pump chamber of the pump module. The pump chamber is thereby reduced in size and liquid from the pump chamber flows through an outlet channel in the stem to the applicator unit and is discharged here through the at least one discharge opening. The return force to push the stem and the piston back to the initial position after actuation is achieved in classic pump modules by means of a metallic helical spring, which acts between the applicator unit and the pump cylinder. To improve the recycling of such a pump module, it is known to design the return spring as a plastic spring. Besides plastic coil springs, various circumferentially closed springs have been proposed, which at least substantially separate a spring interior from an outer environment. Such springs also include bellows springs and dome-shaped springs. Pump modules with such springs are known from documents WO 2021/206255 A1 and U.S. Pat. No. 10,335,816 B1, for example. Although such closed springs provide very good return characteristics, they have the disadvantage that the air in their interior is compressed or decompressed by the deformation during the pressing down and return movement of the applicator unit and thus negatively influences the spring characteristics. Furthermore, such a closed spring makes it more difficult to ventilate a bottle interior of the liquid dispenser. OBJECT OF THE INVENTION The object of the invention is to provide a pump module of the above-mentioned type which, despite the use of a circumferentially closed spring, prevents excessive positive pressure or excessive negative pressure within the closed spring during downstroke and backstroke of the pump piston and, if the pump module is suitably designed, also enables the ventilation of a liquid reservoir through the pump module. In order to fulfill this a pump module is being proposed comprising a pump cylinder having a fluid inlet and an inlet valve at one end. The pump module further comprises a stem and a piston which is attached to the stem. The piston is located within the pump cylinder and defines a pump chamber together with the pump cylinder. The stem extends out of the pump cylinder and comprises an outlet channel of the pump module. The stem and the piston are movable relative to the pump cylinder from an unactuated end position with maximum volume of the pump chamber to an actuated end position with minimum volume of the pump chamber in order to press fluid out of the pump chamber into the outlet channel surrounded by the stem. The fluid is led to the applicator unit and dispensed through the at least one dispensing opening of the applicator unit. Usually, the pump module comprises an outlet valve being located downstream of the pump chamber. In an advantageous embodiment said outlet valve is being provided by the piston being movable in a limited way relatively to the stem. Depending on the relative position of the piston relative to the stem the pump chamber is connected to or separated from the outlet channel inside the stem. When the stem is pressed downwardly in the direction of the pump chamber the piston is shifted relative to the stem to open the outlet channel. During the backstroke the negative pressure in the pump chamber leads to an opposite shifting of the piston relative to the stem, thus closing the outlet valve and the outlet channel. The pump module comprises a return spring in the form of an essentially circumferentially closed spring surrounding the stem. In particular this closed spring can be a bellows spring or a dome-shaped spring. The closed spring acts as return spring and presses the stem and the piston in the direction of the unactuated end position. The closed spring is supported with a first end surface by the stem, or a support collar fixedly attached to the stem, said collar not being part of the applicator unit being connected to the stem. It is however preferred that it is the stem itself and therefore in particular the exact element extending into the pump cylinder which directly supports the outer first end surface of the closed spring. A second end surface on the opposite side of the closed spring is supported by the pump cylinder or by a support collar fixedly attached to the pump cylinder. I