DISPENSER PUMP AND METHOD FOR OPERATING A DISPENSER PUMP

Abstract

Dispenser pump for pumping reservoir fluid to a dispenser head, has a dip tube to insert into the fluid, a cylinder housing connected with the dip tube, a piston pipe guided in longitudinal direction by the cylinder housing for pumping the fluid from the dip tube to the dispenser head, wherein the piston pipe comprises a connecting area for connecting the dispenser head to the piston pipe, a top part connected with the piston pipe, a bottom part connected with the cylinder housing and a spring bellow for pushing the piston pipe in a direction outwards the cylinder housing, wherein a lower axial end of the spring bellow is connected with the bottom part via a lower retainer ring located inside the spring bellow and/or a higher axial end of the spring bellow is connected with the top part via a higher retainer ring located inside the spring bellow.

Claims

1. Dispenser pump for pumping a fluid from a reservoir to a dispenser head, comprising a dip tube for being inserted into the fluid located inside the reservoir, a cylinder housing connected with the dip tube, a piston pipe guided in longitudinal direction by the cylinder housing for pumping the fluid from the dip tube via the cylinder housing to the dispenser head, wherein the piston pipe comprises a connecting area for connecting the dispenser head to the piston pipe, a top part connected with the piston pipe, a bottom part connected with the cylinder housing and a spring bellow for pushing the piston pipe in a direction outwards the cylinder housing, wherein a lower axial end of the spring bellow is connected with the bottom part via a lower retainer ring located inside the spring bellow and/or a higher axial end of the spring bellow is connected with the top part via a higher retainer ring located inside the spring bellow.

2. Dispenser pump according to claim 1 wherein the lower retainer ring is one-piece with the bottom part and/or the higher retainer ring is one-piece with the top part.

3. Dispenser pump according to claim 1 wherein the lower axial end of the spring bellow terminates at a smaller average diameter than the higher axial end, wherein the bottom part provides a contact area over which a lower part of the spring bellow unrolls during an elastic compression of the spring bellow or the higher axial end of the spring bellow terminates at a smaller average diameter than the lower axial end, wherein the top part provides a contact area over which a higher part of the spring bellow unrolls during an elastic compression of the spring bellow.

4. Dispenser pump according to claim 1 wherein an outer diameter of a contact area, onto which the spring bellow unrolls when being compressed, is continuously increasing during a movement of the piston from a minimum inserted position of the piston pipe in the cylinder housing towards a maximum inserted position of the piston pipe in the cylinder housing.

5. Dispenser pump according to claim 1 wherein a tangent to an accessible outer surface of the spring bellow in a point at the outer diameter of a contact area, onto which the spring bellow unrolls when being compressed, in the minimum inserted position of the piston pipe in the cylinder housing is inclined to the longitudinal direction by an angle , wherein 1090 applies.

6. Dispenser pump according to claim 1 wherein the spring bellow comprises a cross sectional area in radial view which is mainly shaped like a part of circle in the minimum inserted position of the piston pipe in the cylinder housing, wherein particularly a maximum diameter of the spring bellow is located between the connection of the spring bellow with the top part and the contact area of the spring bellow on the bottom part in the minimum inserted position of the piston pipe in the cylinder housing.

7. Dispenser pump according to claim 1 wherein the spring bellow is connected to the one part at a diameter d.sub.t and contacts the other part at an outer diameter d.sub.c,min of a contact area, onto which the spring bellow unrolls when being compressed, in the minimum inserted position of the piston pipe in the cylinder housing, wherein 1.0<d.sub.t/d.sub.c,min6.0 applies.

8. Dispenser pump according to claim 1 wherein the spring bellow is connected to the one part at a diameter d.sub.t and contacts the other part at an outer diameter d.sub.c,max of a contact area, onto which the spring bellow unrolls when being compressed, in the maximum inserted position of the piston pipe in the cylinder housing, wherein 0.3<d.sub.t/d.sub.c,max1.5 applies.

9. Dispenser pump according to claim 1 wherein the spring bellow comprises a higher wall thickness between the lower retainer ring and the bottom part and/or between the higher retainer ring and the top part.

10. Dispenser pump according to claim 1 wherein the spring bellow is connected with the lower retainer ring and/or with the higher retainer ring by 2-component injection or insertion molding.

11. Dispenser pump according to claim 1 wherein the bottom part changes its extension in radial direction in dependence of its height in longitudinal direction, wherein the bottom part is shaped at least partially mainly conical or mainly spherical.

12. Dispenser pump according to claim 1 wherein a connecting collar for connecting the dispenser pump with a bottle is provided, wherein the connecting collar protrudes from the bottom part radially spaced to the cylinder housing, wherein particularly the bottom part overlap in radial view the connecting collar at least partially.

13. Dispenser pump according to claim 1 wherein a dispenser head or a mixing bowl is releasably connected with the connecting area of the piston pipe.

14. Dispenser for dispensing a fluid, comprising a bottle comprising a reservoir at least partially filled with the fluid and a dispenser pump according to claim 1 for pumping a fluid from the reservoir to a dispenser head, wherein the dispenser pump is connected to the bottle.

15. Method for operating a dispenser pump according to claim 1 wherein the spring bellow unrolls continuously along a contact area of the bottom part or the top part during a movement of the piston from a minimum inserted position of the piston pipe in the cylinder housing towards a maximum inserted position of the piston pipe in the cylinder housing.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0035] These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter, wherein the described features can constitute each solely or in combination an independent aspect of the invention. In the drawings:

[0036] FIG. 1: shows a sectional side view of a first embodiment of a dispenser pump in a minimum inserted position,

[0037] FIG. 2: shows a perspective view of a bottom part for the dispenser pump of FIG. 1,

[0038] FIG. 3: shows a sectional side view of a second embodiment of a dispenser in a minimum inserted position,

[0039] FIG. 4: shows a sectional side view of a third embodiment of a dispenser pump in a minimum inserted position and

[0040] FIG. 5: shows a sectional side view of a forth embodiment of a dispenser pump in a minimum inserted position.

DETAIL DESCRIPTION OF THE INVENTION

[0041] The dispenser pump 10 illustrated in FIG. 1 comprises a dip tube 12 which may reach into a reservoir of a bottle filled with a fluid to be dispensed. The dip tube 12 communicates with a housing volume V.sub.C of a cylinder housing 14 via an inlet valve 16 which is designed as a one-way-valve. The cylinder housing 14 guides a piston pipe 18 in longitudinal direction. The piston pipe 18 comprises a piston volume V.sub.P communicating with the housing volume V.sub.C via a not illustrated connecting valve which is designed as a one-way-valve. The piston pipe 18 comprises a connecting area 20 by which a dispenser head or another part may be releasably connected to the piston pipe. An outlet valve 22 is positioned radially inside the connecting area 20, wherein the outlet valve 22 is designed as a one-way-valve for defining a minimum pressure inside the piston volume V.sub.P for the dispensed fluid. A fluid sucked in via the inlet valve 16 into the housing volume V.sub.C may be pressed into the a piston volume V.sub.P and displaced upwards by a further pumped amount of fluid via the outlet valve 22 to the dispenser head.

[0042] The piston pipe 18 may be connected to or being one-piece with a top part 24, wherein the cylinder housing 14 may be connected to or being one-piece with a bottom part 26. A spring bellow 28 may be fixed with the top part 24 or being adapted to abut the top part 24 after a predefined insertion of the piston pipe 18 into the cylinder housing 14. The top part 24 comprises a mainly tubular cover part 25 covering the whole spring bellow 28 in the illustrated minimum inserted position of the piston pipe 18 into the cylinder housing 14. The spring bellow 28 is fixed to the bottom part 26. When the piston pipe 18 is pushed into the cylinder housing 14 the spring bellow 28 may provide an increasing spring force for pushing the piston pipe 18 back into the minimum inserted position.

[0043] A connecting collar 42 is provided which protrudes vertically downwards from the bottom part 26. The dispenser pump 10 may be connected to a bottle via the connecting collar 42 for instance by a screw connection. If so, a guiding collar 40 protruding from the bottom part 26 downwards may be provided. The guiding collar 40 may abut a part of the bottle for defining a relative position of the cylinder housing 14 and the dip tube 12 inside the bottle.

[0044] The spring bellow 28 is made from a thermoplastic Elastomer (TPE) and designed as a part of mainly spherical body, particularly mainly egg-shaped, in the minimum inserted position of the piston pipe 18 in the cylinder housing 14, wherein the material of the spring bellow 28 may bend radially outwards in the maximum inserted position of the piston pipe 18 in the cylinder housing 14. The spring bellow comprises an outer surface 34 pointing radially outwards. In the absence of the cover part 25 the outer surface 34 would be accessible for a user over mainly the whole heights in longitudinal direction between the top part 24 and the bottom part 26.

[0045] As illustrated in FIG. 2 the bottom part 26 may comprise a lower retainer ring 30 protruding radially outwards at the most upper end of the bottom part. The spring bellow 28 is retained between the retainer ring 30 and an outer contact area 39 of the bottom part 26. The lower retainer ring 30 is positioned inside the spring bellow 28. In order to facilitate the insertion of the lower retainer ring 30 into the spring bellow 28, the lower retainer ring 30 may comprise a chamfer 38. The contact area 39 may be convex close to the lower retainer ring 30 and concave at its radial outer end away from the contact area 39.

[0046] In the embodiment illustrated in FIG. 3 the spring bellow 28 is formed compared to the embodiment illustrated in FIG. 1 like a part of a mainly spherical elastic ball. The lower axial end of the spring bellow 28 comprises a connection opening 37 into which a sleeve part 36 of the bottom part 26 is inserted for guiding the piston pipe 18 and providing the lower retainer ring 30 inside the spring bellow 26. When the piston pipe 18 is pushed from the illustrated minimum inserted position towards the maximum inserted position into the cylinder housing 14 the spring bellow 28 is compressed between the top part 24 and the bottom part 26 for providing a spring force to push the piston pipe 18 back in its minimal inserted position. The spring bellow 28 may roll over the contact area 39 of the bottom part 26 during the movement of the piston pipe 18 into the cylinder housing 14 when the spring bellow 28 is elastically deformed. The spring bellow 28 contacts the bottom part 26 via the contact area 39, wherein an outer diameter of the contact area 39 wanders radially outwards during at least a part of the movement of the piston pipe 18 from the minimum inserted position towards the maximum inserted position. Due to this elastic behavior of the spring bellow 28 it is safeguarded that the spring bellow 28 bends radially outwards but not radially inwards when elastically compressed.

[0047] In the embodiment illustrated in FIG. 4 the bottom part 26 is formed compared to the embodiment illustrated in FIG. 3 not flat but mainly conical, particularly like a truncated cone. The spring bellow 28 may not only roll over the bottom part 26 radially outwards but also downwards away from the top part 24 during the movement of the piston pipe 18 into the cylinder housing 14 when the spring bellow 28 is elastically deformed. The increase of the spring force provided by the compressed spring bellow 28 can be reduced so that the necessary force for displacing the piston pipe 18 does not significantly increase.

[0048] In the embodiment illustrated in FIG. 5 the bottom part 26 is formed compared to the embodiment illustrated in FIG. 4 not conical but mainly spherical particularly like an umbrella. The three-dimensional form of the bottom part 26 may be adapted to the natural elastic deformation behavior of the spring bellow 28. At the same time the bottom part 26 may form the guiding collar 40 so that the bottom part 26 and the guiding collar 40 may be provided by the same piece. The bottom part 26 may perform the function of the guiding collar 40 of abutting the bottle and thus limiting the distance by which the dispenser pump 10 may be screwed to the bottle via the connecting collar 42.