AU2002222798A1

AU2002222798A1 - Foam forming unit

Info

Publication number: AU2002222798A1
Application number: AU2002222798A
Authority: AU
Inventors: Markus Franciskus Brouwer; Johannes Hubertus Jozef Maria Kelders
Original assignee: R and D Injector AG
Current assignee: R and D Injector AG
Priority date: 2000-11-23
Filing date: 2001-11-23
Publication date: 2002-08-08
Anticipated expiration: 2021-11-23

Description

FOAM FORMING UNIT

The invention relates to a foam forming unit particularly suitable for a liquid container, comprising a pump for air and a pump for liquid, which are each provided with an inlet and an outlet, said foam forming unit further comprising a mixing chamber which is in communication with the outlet of each pump, a dispensing part provided with an outflow channel with a foam opening, the channel being in communication with the mixing chamber, and valves in respectively the inlet and the outlet of each pump for drawing in respectively delivering air and liquid.

Such a foam forming unit is known from the international patent application WO 97/13585. Although this foam forming unit can generate a good foam, i.e. a foam of correct texture, this known foam forming unit consists of a large number of construction components manufactured from different materials. The cost of manufacturing such a foam forming unit is therefore relatively high.

The object of the present invention is to improve the foam forming unit known from the prior art . For this purpose the foam forming unit is characterized according to the invention in that one or more valves are formed integrally with the air pump or liquid pump into a single construction element. By combining functions the number of construction components can in this way be reduced, which results in lower manufacturing costs.

In one embodiment each pump comprises a pressure chamber with a piston displaceable relative to the pressure chamber. Pressure is built up in the chamber of the pump by displacing the piston. In further preference the outlet valve of the liquid pump is formed integrally with the piston of the liquid pump, thereby further reducing the number of construction components .

The foam forming unit according to the invention further

reference to the annexed drawing. In the drawing:

Figure 1 shows a perspective, cross-sectional view of a foam dispensing assembly according to the invention,

Figure 2 shows a cross-section of the foam dispensing assembly of Figure 1 in a first extreme position,

Figure 3 shows a cross-section of the foam dispensing assembly of Figure 1 in a second extreme position, and

Figure 4 shows a cross-section of another embodiment of a foam forming unit according to the invention. The same reference numerals are used in each of the Figures for the same construction components.

In the perspective, cross-sectional view of Figure 1 is shown a foam dispensing assembly consisting of a liquid container 1 and a foam forming unit 2. The foam forming unit 2 comprises a pump 3 for air and a pump 4 for liquid which are each provided with an inlet and an outlet. The inlet of air pump 3 is in communication with the environment, while the inlet of liquid pump 4 is in communication with the content of liquid container 1. Foam forming unit 2 further comprises a mixing chamber 5 which is in communication with the outlet of both air pump 3 and liquid pump 4.

On the top part of the assembly is situated a dispensing part 6 which is provided with an outflow channel 7 with a foam opening 8. Outflow channel 7 runs from mixing chamber 5 to foam opening 8. One or more foam forming elements are normally located in this channel 7.

Both the outlet and the inlet of each pump 3 , 4 are provided with a valve respectively 9,10,11,12 for delivering respectively drawing in air or liquid. Valve 12 in the inlet of liquid pump 4 is otherwise shown in Figures 2 and 3.

Liquid pump 4 comprises a pressure chamber 13 with a piston 14 which is displaceable relative to pressure chamber 13. It is otherwise noted that the term "piston" is understood to mean that part of the pump which is moved (compare Figure 2 and Figure 4) . Pressure chamber 13 is further located between inlet valve 12, outlet valve 11 and piston 14 of liquid pump 4. In addition, air pump 3 comprises a pressure chamber 15 with a piston 16 which is displaceable relative to pressure chamber 15. Pressure chamber 15 of air pump 3 is bounded on one side by inlet valve 10 and outlet valve 9 and on the other side between pistons 14,16 of the two pumps 3,4, these pistons being placed concentrically relative to each other.

An operating member for operating the two pumps 3,4 is manufactured integrally with piston 16 of air pump 3. The operating member 16, or the piston 16 of air pump 3, is arranged slidably in a holder element 17 which holds the foam forming unit 2 in liquid container 1. Upon displacement of operating member 16, this movement is transmitted directly onto piston 16 to operate air pump 3. When operating member 16 is displaced the liquid pump 4 is also operated in that a coupling element 18 is arranged between operating member 16 and the piston 14 of liquid pump 4, which coupling element transmits the displacement of operating member 16 to piston 14 of liquid pump 4. Finally, it should also be noted that dispensing part 6 is in fact formed integrally with operating member 16, or the piston 16 of air pump 3. Figure 1 shows clearly that the valves 9,10,11 are formed by membranes of a predetermined thickness formed on construction elements 14. At a wall thickness of construction elements 14 and 18 of about 1 mm, the thickness of the cylindrical membranes is for instance 0.2 mm. Valves 9,10,11 are injected moulded from plastic simultaneously with air pump 3 or liquid pump 4 to form a single construction element 14,18. For an understanding of the present invention it is noted that the coupling element 18 is deemed a part of air pump 3. Coupling element 18 has on the side directed toward dispensing part 6 an extension 27 with two circular seats 28, 29 of different diameter. In these seats are placed one or more foam forming elements, for instance in the form of fine- mesh screens (not shown) . In the embodiment of Figure 4 the foam forming element is likewise located in the extension 27 of coupling element 18, but is in this case formed by a wall with holes 30 which are co-moulded during the injection moulding of coupling element 18. For a good foaming action OJ OJ t to H μ^*

LΠ o LΠ o LΠ o LΠ

00 oo to to H

LΠ o Π o LΠ o cπ

oo oo to to on H H o LΠ o LΠ O LΠ

The present invention is of course not limited to the preferred embodiments shown in the drawings. Although the pumps 3,4 are shown as concentric, it is also possible to provide them eccentrically or adjacently of each other. An example of such a construction is to be found in the international patent application WO 99/54054. It is further also possible for instance to embody the inlet valve 12 for liquid pump 4 as a membrane formed on piston 14 or holder element 18, wherein a liquid lock will have to be provided in another manner. In any case there is provided according to the invention a simplified foam forming unit with a relatively small number of construction components.

Claims

1. Foam forming unit particularly suitable for a liquid container, comprising a pump for liquid and a pump for air, which are each provided with an inlet and an outlet, said foam forming unit further comprising a mixing chamber which is in communication with the outlet of each pump, a dispensing part provided with an outflow channel with a foam opening, the channel being in communication with the mixing chamber, and valves in respectively the inlet and the outlet of each pump for drawing in respectively delivering air and liquid, characterized in that one or more valves are formed integrally with the air pump or liquid pump into a single construction element.

2. Foam forming unit as claimed in claim 1, wherein each pump comprises a pressure chamber with a piston displaceable relative to the pressure chamber.

3. Foam forming unit as claimed in claim 2 , wherein the outlet valve of the liquid pump is formed integrally with the piston of the liquid pump.

4. Foam forming unit as claimed in any of the claims 1- 3, further comprising an operating member for operating the two pumps .

5. Foam forming unit as claimed in claim 4, wherein the operating member is formed integrally with the piston of the air pump.

6. Foam forming unit as claimed in claim 4 or 5 , wherein a coupling element is arranged between the operating member and the piston of the liquid pump, wherein the coupling element transmits the displacement of the operating member to the piston.

7. Foam forming unit as claimed in claim 6, wherein the outlet valve and/or the inlet valve of the air pump is or are formed integrally with the coupling element.

8. Foam forming unit as claimed in any of the claims 1- 7, wherein the single construction element is an injection moulded element of plastic.

9. Foam forming unit as claimed in claim 8, wherein a valve is formed by a membrane of a predetermined thickness formed on the injection moulded element.

10. Foam forming unit as claimed in any of the claims 1- 9, wherein the inlet valve of the liquid pump is formed by a stopper body which co-acts with at least one sealing rib arranged in the piston of the relevant pump .

11. Foam dispensing assembly consisting of a liquid container and a foam forming unit, wherein the foam forming unit is formed by a foam forming unit as claimed in any of the claims 1-10.