EP1985547A1

EP1985547A1 - Closure for container

Info

Publication number: EP1985547A1
Application number: EP08251517A
Authority: EP
Inventors: Ray Sells; Andrew Edwards
Original assignee: RPC Containers Ltd
Current assignee: RPC Containers Ltd
Priority date: 2007-04-25
Filing date: 2008-04-24
Publication date: 2008-10-29
Also published as: GB2448725A; GB0708007D0

Abstract

A closure for a container for a viscous liquid, where the liquid is dispensed by squeezing the container, contains a nozzle 10. The nozzle 10 includes a converging section 12, a throat section 14, and a diverging section 16, and the liquid passes through these sections in this order when being dispensed.

The liquid is thus subject to the venturi effect as it passes through the nozzle 10, such that the pressure in the throat section 14 is less than the pressure in the diverging section 16. As a result of this lower pressure, liquid in the throat is pushed back into the container when pressure on the container is released.

Description

The present invention is concerned with a closure for a container, and more particularly, a dispensing closure through which the contents of the container can be expelled.
Containers for viscous liquids, such as tomato ketchup, are well known. One relatively recent development is the so-called "headstand" bottle, comprising a bottle with a relatively wide neck (compared to earlier glass ketchup bottles) to which a nozzle is screwed. A cap is integrally formed with the nozzle and connected thereto by a live hinge, and this cap allows the nozzle to be closed. The package is arranged such that when the cap is closed, the bottle can be stood on the cap.
The package is stored in this way (cap down), so that the ketchup flows (albeit slowly) under gravity to the nozzle while the package is being stored. As a result, when a user wishing to dispense ketchup from the package picks it up and opens the cap, there is already ketchup at the nozzle. This means that the ketchup can be dispensed more quickly then with the prior art glass bottles (which are usually stored cap up), and avoids the need for shaking the bottle, which used to be a common feature of dispensing ketchup. The bottle is formed with flexible sides (a so-called "squeezy bottle"), and the ketchup is dispensed by squeezing the bottle to force the ketchup out through the nozzle.
A valve is disposed within the nozzle, so that ketchup does not flow from the bottle as soon as the cap is opened. This valve generally takes the form of a flexible resilient diaphragm, with a cross-shaped slit in the centre of the diaphragm. The slit divides the diaphragm into four (or more) sectors, and these sectors can flex when the bottle is squeezed to expel ketchup from the bottle, thus allowing the ketchup to flow out of the bottle. When the pressure is released, the bottle and the sectors of the diaphragm return to their original shape, thus sealing the nozzle.
However, there are problems with this type of package. As the ketchup passes through the nozzle, it can spread and adhere to the outer edge of the nozzle, or to the outer side of the diaphragm. The ketchup left on the nozzle and diaphragm may then harden on the nozzle and diaphragm, possibly even blocking it.
This hardened ketchup is messy and can be unhygienic. Obviously, the nozzle can be wiped after use.(before the cap is closed), but it would be desirable if the need for this wiping step could be avoided.
Further, the diaphragm is usually formed from a different material to the nozzle and the cap, as it must be more resilient. This makes recycling the cap assembly more awkward, as the diaphragm must be separated from the cap assembly before recycling.
At least in its preferred embodiments, the invention provides a nozzle for use on a dispensing container for a viscous liquid, where said viscous liquid is dispensed from the container by a user exerting pressure on the container to squeeze it, wherein the nozzle includes a converging section, a throat section, and a diverging section, the liquid passing through these sections in this order when being dispensed.
With this layout, liquid flowing through the nozzle is subject to the venturi effect, which reduces the pressure in the throat section. This reduced pressure tends to suck liquid back from the nozzle after dispensing, and so helps keep the nozzle clear and reduces drips.
Preferably, the diverging section is in communication with the atmosphere when the liquid is dispensed. Atmospheric pressure will then push liquid back from the nozzle.
The various sections of the nozzle can be of any suitable shape. However, it is preferred for the converging section, the throat and the diverging section to all have circular cross-sections.
Preferably, the diameter of the converging section reduces in a smooth taper. This avoids the possibility of liquid being trapped in re-entrant portions of the converging section. For similar reasons, it is preferred for the diameter of the diverging section to increase in a smooth taper, and it is further preferred for the angle of taper of the diverging section is greater than the angle of taper of the converging section.
The invention will now be described by way of example only and with reference to the accompanying drawings, in which:

Figure 1 is a cross-sectional view of a nozzle according to a first embodiment of the invention;
Figure 2 is a cross-sectional view of a nozzle according to a second embodiment of the invention;
Figure 3 is a cross-sectional view of a nozzle according to the invention, with an integral cap; and
Figure 4 is a view of the nozzle of Figure 3, with the cap closed.

As can be seen in Figure 1, the nozzle 10 of the first embodiment of the invention differs from the prior art nozzle described above. In particular, the nozzle does not have a diaphragm. The opening of the nozzle has three distinct sections: a converging section 12, a throat 14 and a diverging section 16. It is preferred for all-three sections to have circular cross-sections, although any shape can be used.
The converging section 12 has a wider end (the upstream end for liquid being dispensed) and a narrower end (the downstream end for liquid being dispensed), and is in communication with the inside of the container at its wider end. The inner diameter of the converging section 12 reduces (in a smooth taper) from the wider end to the narrower end, which communicates with the upstream end of the throat 14. Further, it will be seen that the narrower end of the converging section is coterminous with the upstream end of the throat; this ensures that all liquid passing through the converging section enters the throat.
The diameter of the throat 14 is constant from its upstream end to its downstream end, which is in turn in communication with (and coterminous with) the upstream end of the diverging section 16. The diameter of the diverging section 16 increases from its upstream end to its downstream end in a smooth taper, and the angle of taper in the diverging section is preferably greater than the angle of taper in the converging section. The downstream end of the diverging section 16 is in communication with the atmosphere (when the cap is opened). The nozzle 10 is thus in the form of a venturi, and viscous liquid flowing through the nozzle is subject to the venturi effect.
As the viscous liquid passes through the converging section 12, it is forced to accelerate (since the cross-sectional area of flow reduces). As a result, the pressure of the flow reduces. The pressure is at a minimum in the throat 14. Once the liquid enters the diverging section 16, the velocity of the flow reduces (as the cross-sectional area of flow increases), and so the pressure increases.
Thus, as the viscous liquid is dispensed from the container, the pressure in the throat 14 is less than the pressure in the diverging section 16. Further, since the diverging section 16 is in communication with the atmosphere, it is at atmospheric pressure, and so the pressure in the throat 14 is less than atmospheric pressure.
When the container is being squeezed, liquid is expelled through the nozzle 10. However, when the force exerted on the container to expel liquid is released, the pressure differential between the diverging section 16 (at atmospheric pressure) and the throat 14 (below atmospheric pressure) tends to force liquid back through the throat 14 into the converging section 12 and thus into the container; in effect, the liquid is "sucked back" through the nozzle 10. This "sucking back" greatly reduces the amount of liquid left on the nozzle, and so improves hygiene. Further, it reduces the chance of the nozzle dripping.
An alternative form of nozzle 10 is shown in Figure 2. Here, the proportions of the nozzle 20 differ from those of the nozzle 10 shown in Figure 1; however, it will be seen that the nozzle 20 has a converging section 22, a throat 24 and a diverging section 26, and thus that the venturi effect will again arise for liquid passing through the nozzle 20.

The specific measurements for the two nozzles are as follows:

Dimension	First Embodiment	Second Embodiment
A	5.55 mm	5.55 mm
B	1.00 mm	1.00 mm
C	1.50 mm	2.37 mm
D	2.50 mm	3.50 mm
E	4.50 mm	5.50 mm
F	90 degrees	90 degrees
G	60 degrees	60 degrees

It will be seen that the throat section 24 in the second embodiment is wider and longer. This makes it suitable for use with more viscous liquids than the nozzle of the first embodiment. Specifically, the nozzle shown in the first embodiment is more suitable for use with salad cream, and the nozzle shown in the second embodiment is more suitable for use with ketchup. The exact proportions and dimensions of the nozzle can be adjusted to suit the properties (and in particular the viscosity) of the liquid being dispensed.
Figures 3 and 4 show how the nozzle is incorporated into a closure for a container. The nozzle is integrally formed as a part of the closure, and has a cap integrally hinged thereto. As the closure does not require a separate diaphragm, it can be recycled more easily than the prior art closures described above.

Claims

A nozzle for use on a dispensing container for a viscous liquid, where said viscous liquid is dispensed from the container by a user exerting pressure on the container to squeeze it, wherein the nozzle includes a converging section, a throat section, and a diverging section, the liquid passing through these sections in this order when being dispensed.
A nozzle as claimed in claim 1, wherein the ends of the converging section and the throat section are coterminous where they join.
A nozzle as claimed in claim 1 or claim 2, wherein the ends of the throat section and the diverging section are coterminous where they join.
A nozzle as claimed in any preceding claim, wherein the diverging section is in communication with the atmosphere when the liquid is dispensed.
A nozzle as claimed in any preceding claim, wherein the converging section, the throat and the diverging section all have circular cross-sections.
A nozzle as claimed in any preceding claim, wherein the diameter of the converging section reduces in a smooth taper.
A nozzle as claimed in any preceding claim, wherein the diameter of the diverging section increases in a smooth taper.
A nozzle as claimed in claims 6 and 7, wherein the angle of taper of the diverging section is greater than the angle of taper of the converging section.
A cap for a dispensing container containing a nozzle as claimed in any preceding claim.