GB2050852A - Method and device for introducing a gas into a liquid - Google Patents

Abstract

The introduction of a gas into a liquid contained in a vessel, for example in connection with the making of aerated drinks is effected by directing the gas into the liquid via a downwardly pointing hole 5 located centrally in the vessel 1 under the surface of the liquid 2, the values for the diameter of the hole, the distance from the hole to the bottom of the vessel and the gas pressure applied being such that the gas jet 6 reaches the bottom and the gas then ascends to the surface of the liquid 2 in the form of a large number of small separate bubbles 7. The downwardly pointing hole 5 is located near the surface of the liquid 2, but at such a depth in the liquid that air is not drawn down into the liquid by the gas jet 6. <IMAGE>

Description

SPECIFICATION Method and device for introducing a gas into a liquid This invention refers to a way of introducing a gas into a liquid enclosed in a container, for example in connection with the production of aerated beverages as well as to a device for use when applying the method, which device incorporates a pipe connected to the gas bottle via a valve, the pipe being intended to be led into the liquid through a device serving to seal off the mouth of the container.

For the making of aerated waters in the home known types of apparatus exist by which carbon dioxide can be introduced into water in a bottle, the water thereafter being flavoured with essences.

During the adding of carbon dioxide the bottle is placed in position in the apparatus, after which a rubber cone equipped with a through pipe for the introduction of carbon dioxide seals off the mouth of the bottle. The pipe is connected by means of a valve to a gas container with a comparatively high internal pressure. In additon, there is a pressure relief valve in operation between the space above the surface of the liquid in the bottle and the surrounding atmosphere.

When using an apparatus of this type to introduce carbon dioxide into water, the valve is opened between the gas container and the pipe leading down into the water; the valve is kept open until the pressure in the space above the surface of the liquid has risen to the value at which the pressure relief valve opens. Thereafter there is a pause and then the procedure is repeated. To attain the required carbon dioxide admixture, magnitude 2-4 volume-%, the known types of apparatus demand a number of such opening procedures with the pressure relief valve adjusted to a relatively high value, magnitude 12 bar.

As every opening of the pressure relief valve means that a certain amount of gas escapes, the amount being greater the higher the pressure applied, gas consumption due to the aforesaid losses of gas is relatively heavy in the case of these known types of apparatus. The utilization of high pressure also necessitates the use of specially manufactured glass bottles for the purpose.

The main purpose of this invention is to launch a method and a device to be used when introducing a gas into a liquid, achieving a more efficient admixing of the gas and a reduced loss of gas than is the case with known apparatus.

More efficient mixing of the gas means, amongst other things, that the gas container only needs to be connected once to the bottle in order to attain the required gas admixture and that it is possible to work with lower pressure in the bottle. In accordance with the above, this means less gas escapes and also that less gas is lost on the only occasion gas is released, the result being a considerable reduction in gas consumption. The lower pressure permits the use of standard returnable bottles as found in the trade.

The basis of the invention is the concept that the route followed by the gas through the liquid inside the vessel should be as long as possible and that the area exposed by the gas to the liquid should be the maximum possible.

Previously known devices do not meet these requirements and reveal one or more ofthefollow- ing disadvantages. The hole or holes through which the gas is released into the liquid in the vessel are located far too near the bottom, which means that the route followed by the gas through the liquid is too short. The holes in question are too large, the result being a few relatively big bubbles rising to the surface, thereby reducing the total contact area between gas and liquid and involving a risk that the liquid may be pressed against the pressure relief valve. The holes are pointed diagonally towards the side of the bottle, preventing the gas from reaching the bottom of the bottle.The gas is released under much too high pressure, resulting in cavitation in the liquid, still further reducing the contact area between gas and liquid and preventing the jet being broken up into small bubbles.

Efficient admixing is achieved in the present invention by ensuring that at least some of the gas introduced into the liquid in a jet which is to reach towards the bottom of the vessel as a jet and is there broken down into small bubbles which then ascend to the surface. In this way there is a maximum gas path and surface-area exposure to the liquid. A device which achieves this introduces gas into the liquid via a downwardly pointing hole located more or less in the transverse centre of the vessel under the surface of the liquid, with selection of appropriate values for the diameter of the hole, the distance from the hole to the bottom of the vessel and the pressure of gas introduced.

Thus the gas jets must not be so powerful that the gas, even after being freed from the bottom of the vessel, forms large bubbles which ascend to the surface of the liquid. On the other hand, the jets must not be so weak that they do not reach down to the bottom. The optimum is a jet at least part of which is still concentrated when it reaches the bottom of the vessel, where it is broken up into a large number of very small bubbles. The other parts of the original jet have, however, disintegrated into small bubbles due to interaction with the liquid; and these rise to the surface. The result is that practically all the gas is divided up into small bubbles in the liquid, yielding the maximum contact area between liquid and gas, thereby achieving the optimum absorption of the gas in the liquid.

The holes through which the gas is released into the liquid should be located as near the surface of the liquid as possible, but at a sufficient depth below the surface to ensure that air is not drawn down into the liquid by the gas jet.

The invention will be described in greater detail below with reference to the attached drawing.

On the drawing 1 stands for a glass bottle of standard type, approved for a pressure of up to 15 bar. The bottle is filled with water 2, which is to be aerated. For this purpose a pipe 3, connected via a valve (not shown) to a gas container under overpressure, is inserted into bottle 1 through a sealing device 4, preferably of rubber, in the mouth of the bottle. The pipe 3 is furnished with an injection hole 5, pointing downwards, and located in the liquid 2.

The device also comprises a pressure relief valve operating between the space above the surface of the liquid in bottle 1 and the surrounding atmosphere. This valve, however, is not shown on the drawing.

According to the invention, the area of the injection hole shall be determined with regard to the pressure of the gas in the pipe 3 and the distance to the bottom of bottle 1, so that the gas jet 6 reaches as far down as the bottom of the bottle and is there divided up into a very large number of small gas bubbles 7, which rise to the surface of the liquid. By designing the device in such a manner and operating it under such conditions that the gas jet 6 is entirely divided up into fine bubbles at the bottom, the maximum contact area between gas and liquid is obtained and this results in the optimum absorption of the gas in the liquid. To maximise the route of the gas through the liquid, the hole 5 shall be placed as near the surface of the liquid as possible but at a sufficient depth in the liquid to ensure that air is not drawn down by the gas jet.

Tests of a device according to the invention show that an improvement of a magnitude of 25% of the gas absorption capacity, compared with that when using known devices, is attained. The device can also function with pressure in the bottle of the order of 6-8 bar. The improved gas absorption capacity thus permits the combination of low pressure in the bottle with the need of only one gas filling of the bottle until the aforementioned valve is opened, thereby as described above resulting in a considerably reduced loss of gas.

In the case of a submitted design intended for the introduction of carbon dioxide in a bottle filled with waterto a depth of 100 mm. utilising a gas pressure of 60 bar and with the hole for the injection of gas located 10 mm below the surface of the liquid, the diameter of the hole should be approx. 0.3 mm. An arrangement of this kind results in a carbon dioxide admixture of the order of 3-4 volume-% with only one connection of the gas container to the bottle and filling of the latter to a pressure of the order of 6-8 bar.

This invention is not, of course, limited to the production of aerated drinks but can also be applied, to the introduction of another gas to another liquid, as may be desired.

Claims (16)

1. A method of introducing a gas into a liquid contained in a vessel, in which a jet of the gas passes into the liquid through a downwardly pointing hole located below the surface of the liquid; the diameter of the hole, the distance from the hole to the bottom of the vessel and the pressure of the gas introduced being such that at least some of the gas reaches the bottom of the vessel as a jet and thereafter rises to the surface of the liquid in the form of a large number of small separate bubbles.

2. A method according to Claim 1, wherein the downwardly pointing hole is at a sufficient depth in the liquid to ensure that air is not drawn down into the liquid by the gas jet.

3, A method according to Claim 1 or Claim 2, wherein the diameter of the hole is less than 0.4 mm.

4. A method according to any one of the preceding claims, wherein the diameter of the hole is in the range 0.25 to 0.35 mm.

5. A method according to any of the preceding claims wherein the gas pressure in the vessel is less than 10 bar.

6. A method according to any one of the preceding claims, wherein the gas pressure in the vessel is in the range 6 to 8 bar.

7. A method according to any one of the preceding claims substantially as herein described and exemplified.

8. A method according to any one of the preceding claims wherein the product is a gasified drink.

9. A device for use when introducing a gas into a liquid contained in a vessel, including a pipe for bringing gas under pressure to the vessel via a valve, which pipe is intended to be introduced into the liquid in the vessel and sealed to the mouth of the vessel, the pipe being furnished with a small downwardly-pointing hole whose diameter and the distance of which from the bottom of the vessel is such that the gas pressure in the vessel is capable of emitting a jet of gas which reaches the bottom of the vessel, there to be broken down into a large number of small separate bubbles which rise to the surface of the liquid.

10. A device according to Claim 9 wherein the hole is arranged to be located immediately below the surface of the liquid, but at a sufficient depth in the liquid such that air is not drawn down into the liquid by the gas jet.

11. A device according to Claim 9 or Claim 10 wherein the hole is at the centre of the transverse section of the vessel.

12. A device according to Claim 9, Claim 10 or Claim 11 wherein the diameter of the hole is less than 0.4 mm.

13. A device according to any one of Claims 9 to 12, wherein the diameter of the hole is in the range 0.25 to 0.35 mm.

14. A device according to any of Claims 9 to 13 wherein a pressure relief valve is introduced between the space above the surface of the liquid in the vessel and the surrounding atmosphere, this valve being adjusted to a value of less than 10 bar.

15. A device according to any one of Claims 9 to 14 wherein the pressure relief valve is adjusted to a value in the range 6 to 8 bar.

16. A device according to any one of Claims 9 to 15 substantially as herein described with reference to the accompanying drawings.