FOAM DISPENSERS

Abstract

A foam dispenser has a pump body and a sprung plunger (2). A one-piece moulded cylinder component (31) comprises a larger diameter portion (32) for an air cylinder and a smaller diameter portion (33) for a liquid cylinder. The plunger (2) carries respective pistons (22,21) movable in the air cylinder and liquid cylinder to pump air and liquid through valved outlets to a mixing chamber (8) in the plunger for foam production. The liquid cylinder has a discrete inlet piece (9) including an inlet valve. The liquid outlet valve is operated by a valve pin (25) connected to a valve pin retainer (39) which is formed integrally as a one-piece moulding with the cylinder component (31).

Claims

1. Foam dispenser comprising: a pump body including an air cylinder defining an air chamber, a liquid cylinder defining a liquid chamber, and an inlet portion including an inlet valve receiving liquid into the liquid cylinder from a container of liquid to be foamed; a pump plunger reciprocable relative to the pump body including an air piston movable in the air cylinder to vary the volume of the air chamber and a liquid piston operable in the liquid cylinder to vary the volume of the liquid chamber, wherein the pump body includes a one-piece moulded cylinder component including a larger diameter portion to define said air cylinder, a smaller diameter portion to define said liquid cylinder and a transition portion between the larger diameter portion and the smaller diameter portion and a discrete inlet piece connected to the smaller diameter portion of said cylinder component, the discrete inlet piece forming said inlet portion and an inlet valve formation thereof.

2. Foam dispenser of claim 1 wherein the discrete inlet piece is a one-piece tubular moulding.

3. Foam dispenser of claim 1 wherein the discrete inlet piece has an upwardly-directed fitting connecting to the cylinder component and a downwardly-directed dip tube connector.

4. Foam dispenser of claim 3 wherein the upwardly-directed fitting is a socket connected to a downward spigot of the cylinder component.

5. Foam dispenser of claim 1 in which the inlet valve formation has a downwardly-convergent valve seat for an inlet valve member.

6. Foam dispenser of claim 5 in which the inlet valve formation comprises an inward annular flange having a flow orifice at its center and forming a stop for an inserted dip tube.

7. Foam dispenser of claim 1 in which the transition portion of the one-piece moulded cylinder component comprises a re-entrant wall portion thereof forming an outer annular trough and an inner annular ridge.

8. Foam dispenser of claim 1 wherein the pump has a mixing chamber for mixing air and liquid under turbulent conditions to form foam, one or more air outlets leading from the air chamber to the mixing chamber and one and more liquid outlets leading from the liquid chamber to the mixing chamber, and a liquid outlet valve operated by a valve pin connected to a valve pin retainer in the liquid chamber.

9. Foam dispenser of claim 8 in which the valve pin retainer is formed integrally as a one-piece moulding with the cylinder component, or is formed integrally as a one-piece moulding with the discrete inlet piece.

10. Foam dispenser of claim 8 in which the valve pin retainer is formed integrally as a one-piece moulding with the cylinder component as a re-entrant formation in the bottom end of the smaller diameter portion thereof.

11. Foam dispenser claim 1 wherein a pump spring with an end acting against the pump body and an end acting against the pump plunger to bias the plunger towards an extended position relative to the pump body, the pump spring being outside the liquid chamber.

12. Foam dispenser of claim 11 in which the pump spring is in the air chamber.

13. Foam dispenser comprising: a pump body, a pump plunger reciprocable relative to the pump body and a pump spring biasing the pump plunger towards an extended position relative to the pump body; wherein the pump body has an air cylinder defining an air chamber and a liquid cylinder defining a liquid chamber, and an inlet portion including an inlet valve and being for receiving liquid into the liquid cylinder from a container of liquid to be foamed, and wherein the pump plunger has an air piston movable in the air cylinder to vary the volume of the air chamber and a liquid piston movable in the liquid cylinder to vary the volume of the liquid chamber; wherein a mixing chamber being defined in the pump plunger for mixing air and liquid under turbulent conditions to form foam, one or more air outlets leading from the air chamber to the mixing chamber and one and more liquid outlets leading from the liquid chamber to the mixing chamber via a liquid outlet valve; and wherein the liquid outlet valve is operated by a valve pin connected to a valve pin retainer in the liquid chamber downstream of the inlet valve, and the pump spring is positioned in the air chamber.

14. Foam dispenser of claim 13 wherein a bottom end of the pump spring acts against the pump body at the bottom of the air chamber.

15. Foam dispenser of claim 14 wherein the pump body further comprises a one-piece moulded cylinder component comprising a larger diameter portion to define said air cylinder, a smaller diameter portion to define said liquid cylinder and a transition portion between the larger diameter portion and the smaller diameter portion, the transition portion comprising a re-entrant wall portion forming an outer annular trough and an inner annular ridge, and wherein said bottom end of the pump spring acts against said inner annular ridge.

16. Foam dispenser of claim 15 wherein the valve pin retainer is formed in one piece with the smaller diameter portion of the cylinder component.

Description

DESCRIPTION OF THE DRAWINGS

[0021] An example of our proposals is now described with reference to the accompanying drawings, in which:

[0022] FIG. 1 is a perspective view of a foam dispenser pump;

[0023] FIG. 2 is an axial cross-section through the dispenser pump of FIG. 1;

[0024] FIG. 3 is an exploded perspective view showing the upper components of the pump;

[0025] FIG. 4 is an exploded perspective view showing lower components of the pump, and

[0026] Fig. shows a prior art foamer design, already discussed.

DETAILED DESCRIPTION

[0027] The foam dispenser consists of a foam pump 1 mounted on a container 10 which contains a foamable liquid, to be drawn into the pump 1 through a dip tube 55. The container is indicated only schematically in FIG. 1. The pump 1 consists of a body 3, fixedly mounted to a neck of the container by a closure cap 4, and a plunger 2 with an actuator head 6 having a push top 61 and a nozzle 63.

[0028] The closure cap 4 holds the body component down onto the edge of the neck of the container through an outward top flange 312 of the body component and a seal ring 43.

[0029] The pump body 3 consists of a main cylinder component 31 including a larger diameter air cylinder portion 32 with a cylindrical outer wall and a coaxial smaller-diameter liquid cylinder portion 33, also with a cylindrical outer wall and terminating at a downward spigot 331. A re-entrant transition wall 37 extends between the larger diameter and smaller diameter portions, defining an outer annular trough 35 and an inner annular ridge 36. A liquid cylinder of the dispenser is completed by an inlet piece 9 which is a generally tubular moulded part consisting of a lower dip tube socket 92, a top fitting in the form of a socket 91 which fits with a snap onto the downward spigot 331 of the cylinder component, and a convergent valve seat portion 93 between them which forms, on the inside, a conical valve seat surface for a valve ball 58 and a restricted flow orifice 94 immediately below the valve.

[0030] It is a particular feature here that the inlet piece 9 is separately moulded, so that long mould flow paths are avoided in the delicate operation of forming the valve region.

[0031] The plunger 2 moves in the body 3 between extended and retracted positions (the extended position being shown) and carries an outer (upper) air piston 22 and an inner (lower) liquid piston 21 forming a hollow stem, with a bottom annular lip 210 which wipes the wall of the liquid cylinder 33. The internal cavity of the liquid piston 21 constitutes, with the liquid cylinder 33, a liquid chamber 211 which communicates upwardly via a liquid outlet 86 with a mixing chamber 8. The mixing chamber 8 is the beginning of an outlet passage 67 leading to the discharge nozzle 63 via a foam regulator 81. The foam regulator 81 may be of any known type; that shown is a conventional insert comprising meshes 83 on either end of a sleeve 82 which fits into the plunger head 6.

[0032] The plunger 6 has a shroud 64 with a front axial rib 65, fitting down through a locking flange 42 and a corresponding slot 44 of the closure cap 4. In the plunger-extended position the plunger can be turned so that a locking slot 66 (see FIG. 3) slides onto the locking flange 42 and prevents depression of the plunger.

[0033] The air piston 22 (see also FIG. 3) has a generally domed shape constituting a central portion of the plunger, and receives a coaxial air valve ring 87 comprising inward and outward annular elastomer flaps which act as an inlet valve and an outlet valve for air flow vis vis the air chamber 311 defined in the air cylinder 32. On the plunger upstroke, air flows into the air chamber 311 in a known manner through clearances in and around the plunger head and then through the air inlet valve. On the plunger downstroke air is driven out of the air chamber 311 via air outlet channels 85 defined between the liquid piston and air piston components 21,22, entering the mixing chamber 8 at speed to mix with the liquid between the liquid outlet 86 and the foam regulator 81.

[0034] Valves for the liquid flow are provided by the inlet ball valve 58,93 at the inlet piece 9, and by a valve pin 25 comprising an elongated shaft 252 with a tapered head 251 acting as a liquid outlet valve member seating in the liquid outlet 86. The pin 25 has a retaining enlargement 253 at the bottom end which is trapped by an inward flange 391 at the top of an upwardly-projecting retainer tube 39; the bottom end of the valve pin is snapped into this tube during assembly and retained thereafter.

[0035] A feature of this construction is that the upstanding retainer tube 39 for the pin 25 is moulded in one piece with the main cylinder component 31, as a re-entrant formation of the bottom end of the liquid cylinder portion 33 thereof. This obviates having a separate component for the pin retainer, which has previously been necessary in dispensers using one-piece liquid cylinder portions.

[0036] The pump spring 5, to compress during depression of the plunger and urge the plunger back to the extended position afterwards, is housed in the air chamber 311 surrounding the liquid piston 21 so that it is out of the liquid flow path. Its bottom end rests on a spring seat 36 provided on the inner annular ridge of the re-entrant transition wall 37 of the body component 31, around the top of the liquid cylinder portion.

[0037] Operation of the dispenser proceeds according to known principles. After a preliminary depression of the plunger, the plunger re-extends driven by the spring, drawing liquid into the liquid chamber 211 and air into the air chamber 311 through the corresponding inlet valves. As the plunger extends, the valve member 251 at the top of the valve pin 25 is drawn down to seal the liquid outlet 86.

[0038] Subsequently the plunger 6 is depressed by pushing on the push top 61. Liquid pressure lifts the valve member 251 of the valve pin 25 off its seat, so that liquid jets into the mixing region 8 at the same time as air under pressure is driven into the same region from the air outlets 85 via the air outlet valve. The turbulent mixing of the air and liquid forms a foam precursor which is then made more uniform and adjusted in bubble size by passing through the regulator meshes 83, subsequently passing out through the outlet channel 67 to the discharge nozzle 63.