Dispensing – Plural sources – compartment – containers and/or spaced jacket – With common discharge
Patent
1998-04-03
2000-04-25
Bomberg, Kenneth
Dispensing
Plural sources, compartment, containers and/or spaced jacket
With common discharge
222190, 2223219, B67D 506
Patent
active
060533641
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention firstly relates to a device for dispensing an air-liquid mixture, in particular a foam, at least comprising a liquid container and an operating unit, which unit comprises at least an air pump and a liquid pump, which are essentially concentric, and each comprise a piston chamber with a piston which is displaceable therein, while each pump comprises an inlet and a discharge, and an operating component is present for operating the two pumps, which operating component is integral with the piston of the liquid pump, and therein comprises an outflow channel with a dispensing opening, which channel can be connected to the discharge of the pumps, while shut-off means, which make it possible to suck up air or liquid, respectively, into the appropriate piston chambers and to dispense these fluids to the outflow channel, are present in the inlet and discharge of the air and liquid pump, the connection between the outflow channel and the relevant pumps being interrupted while air or liquid is being sucked up, and the air pump comprises a double-acting shut-off device, which shuts off both the inlet of air to the air pump and shuts off the discharge of air therefrom.
DESCRIPTION OF PRIOR ART
A device of this kind is disclosed by EP-A-0 613 728 and is designed to dispense foam. To this end, foam-forming means are present in the outflow channel. Moreover, a mixing chamber is in this case present which can be connected to the discharges of the air and liquid pumps and the outflow channel.
The double-acting shut-off device for the air pump comprises a resilient shut-off component, comprising a cylindrical wall section, an annular outer section which extends outwards from the said cylindrical wall section and an annular inner section which extends inwards from the said wall section. The resilient shut-off component is fastened with the said cylindrical wall section to the inner wall of the air piston.
However, the action of the abovementioned foam-dispensing device is not optimal, since problems may occur during dispensing. Dispensing can be impeded by the double-acting shut-off device sticking to other components of the device. If, during use, a section which has stuck fast suddenly comes loose, uncontrolled pressure differences may occur, which have undesirable consequences. Consequently, a relatively large amount of gas or liquid may suddenly emerge. In both cases, this may lead to contamination and spattering, and therefore to foam being formed incorrectly or not at all. The liquids to be dispensed are often substances which are irritating to the eyes. It will be clear that this uncontrolled dispensing should be avoided. Any sticking of the shut-off device likewise leads to problems with refilling the air piston chamber with air after use.
In addition, the said shut-off device is a so-called passive shut-off device, which is opened by pressure differences generated in the unit. In other words, the shut-off device comprises a combination of two non-return valves. The relevant annular sections of the said shut-off device shut off the inlet and discharge, respectively, of the air piston chamber under a certain prestressing. When the pressure drops or rises suitably, the inlet and discharge, respectively, are connected to the air piston chamber.
SUMMARY OF THE INVENTION
The present invention aims to provide a device of the type mentioned in the introduction which does not have the problems of the prior art device and furthermore has a generally improved action. To this end, the invention has the characteristic that the double-acting shut-off device for the air pump is a shut-off device which can be operated actively by the operating component, and in that the air piston is an air piston which can move freely at least over a short distance with respect to the operating component.
In this way, any problems with sticking and the like are completely eliminated. Dispensing can be carried out in a very controlled manner, since the inlet or discharge, respectively, is opened or
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patent: 5271530 (1993-12-01), Uehira et al.
patent: 5443569 (1995-08-01), Uehira et al.
patent: 5570819 (1996-11-01), Uehira et al.
patent: 5779104 (1998-07-01), Reidel
patent: 5813576 (1998-09-01), Iizuka et al.
Airspray N.V.
Bomberg Kenneth
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