Patent Application
20160220970
1. Field of the Invention
The present invention relates generally to carbonation of a liquid such as water with carbon dioxide gas (CO2), and more particularly to a method and apparatus for rapid carbonation.
2. Description of the Prior Art
It is well known in the art to carbonate fluids to produce beverages, especially water. For example, Fessler et al. in U.S. Pat. No. 4,187,262 describe a carbonator and liquid level control. McMillin, in U.S. Pat. No. 4,708,827 describes a method and apparatus for dispensing carbonated water with a particular type of pump. Burrows, in U.S. Pat. No. 5,073,312 describes a water carbonation system. Goulet et al. in U.S. Pat. No. 5,156,871 describe a low cost beverage carbonator. Goulet in U.S. Pat. No. 5,419,461 describes a narrow profile, substantially flat carbonator. Vogel et al. in U.S. Pat. No. 5,792,391 describe a basic carbonator as a tube cylinder having a closed and open end. The cylinder has a top that allows water and carbon dioxide gas entry. Improvements continue to be made in carbonation systems such as Novak et al. in U.S. Published Patent Application no. 2013/0129870 which describes dissolving gas in a pre-cursor liquid.
Most prior art carbonation systems simply pump CO2 under pressure into a tank containing water. Some of the systems have ways of mixing the gas into the water such as the Burrows patent which uses impellers and nozzles, or the Goulet et al. '871 patent that uses an electric motor to rock the tank. With the remaining gas in the tank under pressure in most prior art systems, carbonated water can simply be removed by pressure through an exit tube in the bottom of the tank. Many systems use a pump to either pump water or gas into the tank. Most beverage carbonators also have refrigeration or chiller units to reduce the temperature of the carbonated output water for cold beverages. These units also counter the rise in temperature caused by increasing the gas pressure in the tank. Prior art systems typically dissolve from 2.0 to 4.0 volumes of CO2 gas in 1.0 volume of liquid. When the fluid is water, in equilibrium, at 40 degrees F., a gauge pressure of one atmosphere (one atmosphere over ambient or around 14.5 pounds per sq. inch) yields approximately 3.0 volumes of gas to one volume of water. Colder water can hold more dissolved gas at a particular pressure than warmer water. For example, at the same pressure, 35 degree F. water can hold approximately 3.25 volumes. Therefore, an additional advantage to chilling is more dissolved gas.
What the prior art systems fail to provide is rapid carbonization. Carbonated water, or other fluid, is simply carbon dioxide dissolved in the fluid. It is well-known that the rate that CO2 gas dissolves in water is 1) the amount of CO2 gas already dissolved (the process slows as the system approaches saturation), 2) the temperature, 3) the pressure, and 4) the size of the surface area boundary between the gas and the fluid.
Various prior art systems attempt to manipulate some of these parameters such as increasing the surface area of the boundary by mixing or agitating. However, while this technique offers some rate speed-up, the total surface area is only marginally increased. It would be very advantageous to have a system and method for carbonation that took advantage of a tremendously increased fluid surface boundary area to effectuate rapid absorption of the gas into the fluid.
The present invention relates to a system and method for rapid carbonization of a fluid such as water. The invention causes CO2 gas to be pumped or otherwise put into a vessel at an increased pressure greater than one atmosphere. Liquid is then injected into the vessel using the technique of atomization. Atomization is a process where the liquid is caused to take the form of a very large number of tiny droplets. This is done by giving the liquid angular momentum as it is sprayed out of one or more nozzles. The very large number of very small droplets have a tremendously increased surface area increased surface area of the gas-liquid boundary causes very rapid dissolving of the gas in the liquid. The required angular momentum is imparted to the liquid by a curved feed system and by specially shaped nozzles.
The present invention sprays atomized water or other fluid into the vessel containing CO2 gas under pressure until the total pressure has increased to a predetermined amount, and the vessel contains a predetermined amount of standing liquid. Since the gas dissolves in the liquid before it comes to rest in the bottom of the vessel, the carbonated liquid may begin to be almost immediately drawn off if needed. A level sensor determines when more gas and/or liquid is needed in the vessel to maintain a steady state.
Attention is now directed at several drawings that illustrate features of the present invention:
Several drawings and illustrations have been presented to aid in understanding the present invention. The scope of the present invention is not limited to what is shown in the figures.
The present invention relates to spaying atomized liquid droplets into a vessel containing CO2 gas under pressure. The increased surface area of the droplets leads to rapid absorption of the gas into the liquid. Embodiments of the invention include a pressure vessel with a top having a specialized liquid flow member and nozzle(s) to provide the atomized droplets.
Turning to
As an example, the vessel 1 is filled with CO2 gas to a pressure of roughly 3 bar (3 atmospheres, or 43.5 psi gauge). This approximate gas pressure (or any desired working pressure) can be maintained by a pressure regulator on the CO2 gas supply system. Water can then be pumped in through the atomizer. This water absorbs gas as it enters the vessel. The resulting carbonated water collects in the bottom of the vessel. As the water is sprayed in, the pressure in the vessel would increase if there were no CO2 gas absorption. If for example, the vessel holds 1000 mL, and assuming a 3 bar gas pressure starting pressure, after around 500 mL of water has been introduced, the pressure would be around 6 bar if gas absorption is neglected (according to the state equation for the gas, the gas temperature will also rise). In a practical situation, the water rapidly absorbs the gas, and the pressure remains approximately constant. If the water spray is stopped when the vessel contains 500 mL of liquid, the pressure will be around 3 bar or less. As previously stated, this pressure can be maintained using a CO2 gas regulator. It is preferred to regulate the gas pressure because If the gas pressure is allowed to rise excessively, the water pump might see too high a pressure to pump against.
Starting from approximately the second cup of carbonation draw (710 mL), the carbonated water quality is sufficient if the fill time is around 20-30 seconds based on the known absorption rate for systems with an agitator. However, the rapid absorption of the present invention allows a much shorter fill time. It has been determined that, given a design vessel volume of 1000 mL with a fill to 600 mL it is possible to produce two to three 12 ounce (355 mL) good quality carbonated water draws back-to-back if the vessel is filled at a rate sufficient to keep up with the demand. Good quality means around 4.3 volumes of CO2 for each volume of water.
The above examples are given to aid in understanding the invention. They are for example only. Any size vessel is within the scope of the present invention with corresponding pressures and volumes scaled accordingly. Also, many different equilibrium liquid levels will work and are within the scope of the present invention.
The present invention provides a rapid way of providing almost continuous carbonation of water or other liquid by atomizing the liquid as it is sprayed into a container containing compressed carbon dioxide gas. This provides an commercial and economic benefit in the dispensing of cold, carbonated beverages. Any technique for atomizing the liquid is within the scope of the present invention.
Several descriptions and illustrations have been provided to aid in understanding the present invention. One with skill in the art will realize that numerous changes and variations may be made without departing from the spirit of the invention. Each of these changes and variations is within the scope of the present invention.
