FR2703262A1 - Gaseous mixtures. - Google Patents

Abstract

A process for the preparation of a substantially stable and homogeneous gas mixture comprising greater than about 50% by volume of a liquefiable gas, which process comprises: providing a source of liquefiable gas, a source of permanent gas, and a gas tank, supplying the permanent gas to the gas tank and supplying the liquefiable gas to the gas tank, characterized in that the liquefiable gas is introduced at an elevated temperature and / or at a speed high so that its volume is greater than about 50%.

Description

GASEOUS MIXTURES

  The present invention relates to certain gas mixtures, and the use of such gas mixtures for food, beverage, welding and similar applications. It is known in the prior art the use of gaseous mixtures containing a liquefiable gas component such as C 02 or N 2 O, in combination with other gaseous components (called permanent gases) However, if the concentration of liquefiable gas in such gas mixtures are high (about 50% or more by volume), the liquefiable gas fails to mix with the other components within a reasonable amount of time if conventional mixing methods are applied. charge the liquefiable gas into a standard cylinder

  only at a limited pressure so as to avoid this problem.

  For example, carbon dioxide is widely used as a dispensing gas for beverages.

  such as beer or non-alcoholic beverages

  mix. Regarding the art of distributing beer it is very important that the appearance of the beer in the glass appeals to the user While the taste is the most talked about feature with regard to the beer, the appearance is the first thing the customer notices. The hue and intensity of the color, the clarity, the bubbles, the type of false collar, the retention of the foam and the adhesiveness of the foam contribute to each one.

  to the production of the initial impression He is desirous

  that the foam on the top of a beer glass under pressure is homogeneous, creamy, relatively stable and

  it has a seductive aroma.

  While pure C 02 is often used as

  than distribution gas, this tends to lead to an over-

  carbonation of beer, which is less appealing for

  the consumer, and may lead to excessive training

  When the beer is dispensed, causing excessive waste While the use of a gaseous mixture of carbon dioxide and nitrogen is known to overcome this problem, a high nitrogen content tends to be a problem. to form a flat beer, which again is unacceptable to the consumer While a gas mixture, for example, carbon dioxide in high proportion with nitrogen would allow

  theoretically to deal with both problems, attempts to

  production of such a gaseous mixture which can be loaded at a high pressure have not been successful in the prior art, because of the problems of

  mixture of liquefied Ca 2, as discussed above.

  Consequently, a significant advance in the art would follow if it were possible to produce a gas mixture with a liquefiable gas concentration greater than 50%, but which offers

  gas mixture which is very stable to use at

  eratures, pressures and normal workflows.

  Accordingly, it is the object of the present invention to overcome, or at least minimize, one or more of the difficulties and deficiencies relating to

the prior art.

  Accordingly, in a first aspect of the present invention, there is provided a process for the preparation of a substantially stable and homogeneous gas mixture, comprising a proportion greater than about% by volume of a liquefiable gas, which process comprises the provision of a source of liquefiable gas, a source of permanent gas, and a gas tank, the supply of permanent gas to the gas tank, and the supply of liquefiable gas to the tank, characterized in that the liquefiable gas is introduced at a high temperature and / or at a high speed so that its final volume is greater than

about 50%.

  The invention also provides a gaseous mixture 3 - comprising a proportion greater than about 50% by volume of a liquefiable gas in a suitable gas tank, the mixture being essentially stable and

  homogeneous under loading pressures ranging from

  It has surprisingly been found that by first supplying the gas to the gas tank and supplying the liquefiable gas at a high temperature and / or at a high speed. high, a gaseous mixture was produced which was both substantially stable and homogeneous, and comprised more than about 50% of liquefiable gas Such stability is maintained in a

  extended range of both pressures and temperatures.

  The gaseous mixture, for example, is substantially stable and homogeneous in a suitable container at loading pressures ranging from about 10,000 kPa to about 30,000 kPa. The gaseous mixture is substantially stable and homogenous at use, temperatures and temperatures. normal workflows, eg from about 50 C to 250 C. The liquefiable gas may be present in the

  gaseous mixture in any appropriate quantities above

  The liquefiable gas may be present in amounts of about 50% by volume to 97.5% by volume, preferably from about 55% to 85% by volume, more preferably from about 60% to 75% by volume. by volume The liquefiable gas may be carbon dioxide (CO 2), nitrous oxide (N 20) or other liquefiable gases or mixtures thereof depending on the use of the gaseous mixture On

prefers carbon dioxide.

  The permanent gas may be chosen from nitrogen, helium, argon, oxygen or other permanent gases,

  according to the use of the gaseous mixtures Nitrogen is preferred.

  The permanent gas may be present in the gaseous mixture in amounts of about 2.5% by volume to less than 50% by weight.

volume.

  The permanent gas can be supplied to the gas tank, for example a compressed gas cylinder, using standard techniques. The liquefiable gas is pumped into the cylinder by preheating it to a temperature of about 401 ° C. to 2500 ° C. Rarely 800 C at 1100 C and at a high speed A cryogenic pump can be used The pump can for example generate speeds of about 10 to 50 meters per second when filling the gas. As stated above, it was surprisingly found that the resulting gas mixture was both substantially stable and homogeneous in a wide range of temperatures and pressures. Although we did not want to be limited by theory, it is postulated that the high-speed, high-temperature supply of the liquefiable gas brings the gas into a supercritical state, which apparently explains why the mixture is more stable and homogeneous than can be

achieve otherwise.

  Accordingly, in another aspect of the present invention, there is provided a gas mixture comprising greater than about 50% by volume of a liquefiable gas in a suitable gas tank which is substantially stable and homogeneous under loading pressures. about 10,000 k Pa to

about 30,000 kPa.

  The liquefiable gas and permanent gas components of the gaseous mixture may be as described

above.

  Preferably the gaseous mixture comprises from about 55% to 85% by volume of C 02; and about 15% to 45

% by volume of nitrogen (N 2).

  In a preferred aspect, the gaseous mixture may further comprise an additional gas component selected from helium (He), hydrogen (H 2), argon (Ar) and oxygen (O 2). additional gas may be added to further modify the characteristics of the gaseous mixture according to the application of the latter. The additional gas component may

  from about 0.5% to 25% by volume, preferably

  from 1% to 20% by volume As stipulated above

  gaseous mixtures can be used for applications including food, beverages, and for similar applications Gaseous mixtures are particularly applicable to the distribution of beverages such as beer and non-alcoholic beverages post-mix, as well as 'to the packaging of food products. Accordingly, another aspect of the present invention provides a method for dispensing a beverage that comprises providing a gaseous mixture comprising greater than about 50% by volume of a liquefiable gas in a suitable gas tank. the mixture being substantially stable and homogeneous at loading pressures of from about 10,000 k Pa to about 30,000 k Pa; dispensing apparatus comprising a beverage; pressurizing the beverage with the gas mixture; and

the distribution of the drink.

  A desirable distribution is made to

  temperatures above about 50 C, preferably above

  beyond about 70 C, more preferably above about 100 C. The drinking source may be a malt beverage such as beer. The dispensing apparatus may be a standard beer dispenser. The dispensed beverage may have a creamy, stable and

an improved taste.

  The present invention will now be described in more detail with reference to the accompanying examples.

  should be understood however that the description which

  follows is only intended to illustrate and should not be construed as a limitation to the generality of

the invention described above.

Examples

  Cylinders are filled with gas to produce various gas mixtures, referred to as "Aligal" gas. The filling process is illustrated graphically in Figure 1 and proceeds as follows: 1 Cylinders are connected to the gas manifold filling, the valves being in the open position, ready for filling. 2 A control cylinder is placed on an electronic scale to monitor the weight of gas introduced into the cylinders This scale is connected to a programmable controller, which is

  programmed to open and close pneumatic valves

  according to the mixture selected so as to introduce the correct amount of each component

gaseous in the cylinders.

  3 The programmable controller first introduces the permanent gas into the cylinder according to the program, and then, as the last component, the

CO 2 in gaseous form.

  4 Once the control cylinder has reached its programmed weight, the main valve closes, the cylinder valves are closed, and the cylinders are ready for shipping (after sample analysis).

  PRODUCT RANGE FOR STANDARD ALIGAL GAS

  Aligal 13 30% C 02 70% N 2 Aligal 15 50% C 02 50% N 2 Aligal 15 + 55% C 02 45% N 2 Aligal 17 70% Ca 2 30% N 2 Aligal 18 80% C 02 20% N 2 Aligal 19 90% C 02 10% N 2 The Aligal gases are now filled preferably in high pressure gas cylinders (aluminum or steel) containing 6 m 3 (35 1 WC Aluminum) at 10 mn (35 1 WC Steel), if possible up to min (50 1 WC, Steel) of gas Volumes are measured in cubic meters (m 2) according to Australian standard A 52992/1987 in which 1 m 3 is defined as 1 m 2 of gas measured at 101.325 k Pa and at 150 C. 7 - Several tests are then carried out for

  demonstrate the production viability of these mixtures.

  Tests carried out by loading Aligal 17 by the conventional method (first Ca 2 at low pressures and temperatures, then N 2) have shown that it is impossible to obtain a homogeneous mixture within a period of time. correct after filling The CO 2 content of the gas phase never reached 40% soon after filling was completed (instead of

70% required).

EXAMPLE I

  Tests were carried out to study the emptying of a cylinder of 10 m 3 The gas mixture was

  72% of Ca 2, 28% of N 2. It was established that the composition

  the gas pressure did not change between the test pressures of 12700 k Pa at 2100 k Pa during the test period It should be noted that fluctuations of less than 3% in CO 2 content are not considered critical, being below the measurement tolerance of the analytical instruments used The test results are as follows: 8 -

Tempera-

room temperature Pressure (k Pa)

% CO 2

  Comments Regulator different Regulator B L.

11.15 ° C

  12.15 12.45 1.15 2.00 2.30 3.00 26 C 28 C 28 C C C C 72% Heating and regulator P B.

EXAMPLE II

  Additional tests were carried out to

  examine the safety of the cylinders at high temperatures.

  It was noted that, throughout the temperature range, the pressure changed, but that the gas mixture remained

stable.

  8.30 9.00 10.15 11.00 11.30 12.00 12.30 1.00 2.00 72% 72% 72% 72% 72% 72% 72% 72% 72% CCCCCCCCCCC 22 C 24 C 24 C 2.30 3.00 3.30 72% 72% 72% 8.30 9.30 10.30 72% 72% 73% 9 Pressure Temperature (k Pal% CO, cylinder

C 11800 71

C 12500 71

250 C 13300 71

300 C 14300 71

350 C 15400 71

400 C 16400 71

450 C 17400 71

500 C 17400 71

EXAMPLE III

  An additional test examined the effect of fast emptying of a cylinder, using the same gas mixture as in Example I. The cylinder was emptied in about 35 minutes. Normally, a cylinder of this size would have to be emptied over a period of several days A minor compositional variation appeared to occur during fast emptying, but this remained below the 3% C 02 tolerance of the measuring instruments.

  is not considered significant.

Time% CO Pressure

13.15 75 13000

13.21 73.8 11000

13.28 69.5 10000

13 34 69.5 8000

13.39 71.0 6000

13.45 71.5 4000

13.50 73 1500

  Finally it should be understood that various other modifications and / or alterations can be made without departing from the spirit of this

  invention as described herein.

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Claims (20)

claims:   A process for preparing a substantially stable and homogeneous gas mixture comprising greater than about 50% by volume of a liquefiable gas, which process comprises: providing a source of liquefiable gas, a source of permanent gas, and a gas tank, the supply of the permanent gas to the gas tank, and the supply of liquefiable gas to the tank, characterized in that the liquefiable gas is introduced at an elevated temperature and / or at a rate elevated so that its final volume is greater than about 50%.   A process according to claim 1, characterized in that the liquefiable gas in the gaseous mixture is present in an amount of about 50% to 97.5% by volume. A process according to claim 2, characterized in that the liquefiable gas is present in the mixture   gaseous in an amount of about 55% to 85% by volume.   A process according to claim 2, characterized in that the liquefiable gas is present in the mixture   gaseous in an amount of about 60% to 75% by volume.   A method according to any of the claims   tions, characterized in that the liquefied gas   ble is heated to a temperature of about 400 ° C to 250 ° C.   A process according to claim 5, characterized   in that the liquefiable gas is heated to a temperature of   re in the range of 80 'C to 110' C.   A method according to any one of the claims   the above, characterized in that the heated gas is supplied to the tank at a speed of about 10 to 50 meters per second.   8 A method according to any one of the claims   tions, characterized in that the liquefied gas   ble is selected from carbon dioxide, protoxide   nitrogen, other liquefiable gases or mixtures thereof.   A process according to claim 8, characterized   in that the liquefiable gas is carbon dioxide.   A method according to any of the claims   preceding conditions, characterized in that the permanent gas is present in the mixture in an amount of about 2.5% to 50% by volume.   11 A method according to any of the claims   in which the permanent gas is selected from nitrogen, helium, argon, oxygen or their mixtures.   A gaseous mixture comprising a proportion greater than about 50% by volume of a liquefiable gas in a suitable gas tank, the mixture being substantially stable and homogeneous under   loading from about 10,000 kPa to about 30,000 kPa.   13 A gaseous mixture according to claim 12, characterized in that the liquefiable gas is present in   from about 50% to 97.5% by volume.   14 A gaseous mixture according to claim 13, characterized in that said liquefiable gas is present   in an amount of about 55% to 85% by volume.   A gaseous mixture according to claim 13, characterized in that said liquefiable gas is present   in an amount of about 60% to 75% by volume.   16 A gaseous mixture according to any one of   Claims 12 to 15, characterized in that the gas   liquefiable is selected from carbon dioxide, nitrous oxide, other liquefiable gases or mixtures thereof. 17 A gaseous mixture according to any one of   Claims 12 to 16, characterized in that the mixture gas comprises a permanent gas.   A gaseous mixture according to claim 17, characterized in that the permanent gas is present in one   amount of about 2.5% to 50% by volume.   A gas mixture according to claim 17 or   claim 18, characterized in that the perma-   is selected from nitrogen, helium, argon, oxy- gene or their mixtures.   12 - A gaseous mixture according to any one of   Claims 12 to 19, characterized in that the gas   liquefiable is carbon dioxide, and the perma- Nit is nitrogen.   21 A gaseous mixture according to any one of   Claims 12 to 18, characterized in that the mixture   gas comprises an additional gas.   A gaseous mixture according to claim 21, characterized in that the additional gas is selected from helium, hydrogen, oxygen and argon or their mixtures.   23 A gaseous mixture according to claim 21 or   Claim 22, characterized in that the additional gas   is present in an amount of approximately 25% by volume.   A mixture according to claim 23, characterized   in that the additional gas is present in one   amount of about 1% to 20% by volume.   A method for dispensing a beverage, which process comprises: providing a gas mixture according to any one of claims 12 to 24; and   dispensing apparatus comprising a beverage; pressurizing the beverage with the gas mixture; and the distribution of the drink.   A method according to claim 11, characterized   in that the drink is a malt beverage such as beer.   A method for preparing a substantially stable and homogeneous gas mixture comprising greater than about 50% by volume of a substantially liquefiable gas as described above by   reference to any of the examples.