GB2293332A - Vending carbonation - Google Patents

Abstract

A carbonator for low use beverage dispensing systems is disclosed. Water 6 and carbon dioxide 5 are fed under pressure into vessel 1 until the pressure in the vessel equals the water inlet pressure thus establishing a pressure equilibrium, the water in the vessel is then cooled by refrigeration system 7 so that it absorbs carbon dioxide gas from the headspace 9. This causes the pressure in the vessel to drop and more water is automatically drawn into the vessel, this process repeats until the vessel is completely full of water and all the gas has been absorbed. The device provides a reservoir of carbonated water for beverage dispensing. <IMAGE>

Description

Carbonation The present invention relates to carbonation and more particularly to carbonation in beverage vending machines and similar low usage dispense systems.

Typically, beverage vending machines have used conventional carbonator devices to provide carbonated or soda water. These carbonator devices comprise a carbonator bowl, a level control and a pump/motor to force water into the bowl against the CO2 top pressure.

Typical carbonator devices are designed to provide instant carbonation of water.

Vending devices generally do not require instant carbonation and have long stand-by periods when there is little or no dispense. Thus, typical carbonator devices are over specified for vending applications. This over specification adds to costs both in terms of equipment and running expenses.

It is an objective of the present invention to provide a carbonation arrangement more suitable for vending applications.

In accordance with the present invention there is provided a carbonator including a vessel with a CO2 gas supply and a water supply in pressure equilibrium, the water being cooled such that the water absorbs the CO2 gas from a head space above the water surface to provide carbonated water in the vessel, the absorbtion of CO2 gas disturbing the pressure equilibrium by reducing carbonation pressure in the vessel and so more water and CO2 gas is drawn into the vessel until the head space is substanially eliminated.

In accordance with an alternative embodiment of the present invention there is provided a method of carbonating water whereby: (1) water and CO2 gas are fed to a vessel under pressure; (2) water is fed into the vessel until its pressure is equivalent to carbonator pressure in the vessel; (3) the water is cooled to absorb the CO2 gas and reduce the carbonator pressure and so draw more water and CO2 gas into the vessel; and, (4) repeating steps 1 to 3 until the vessel is substantially full of carbonated water.

Preferably, the water is pumped to the vessel by a diaphragm pump using CO2 gas pressure as a motivation force.

Preferably, the water supply includes a restrictor pipe or other control device to inhibit water feed to the vessel in comparison with CO2 gas feed. Thus, carbonation is facilitated in a reduced number of carbonation cycles.

An embodiment of the present invention will now be described by way of example only with reference to the accompanying drawing in which: Figure 1 is a schematic illustration of a carbonator; and, Figure 2 is a graphical representation of typical performance cycle for the carbonator illustrated in Figure 1.

Consider Figure 1 which illustrates in schematic form a carbonator 1. The objective of the carbonator 1 is to provide a reservoir of carbonated water 2. Thus, carbonated water can then be used to provide beverages when added to syrup. The carbonator 1 has a pressure vessel 3 with an outlet 4 for connection to a beverage dispense nozzle (not shown), a CO2 gas supply 5 and a water supply 6. The carbonated water 2 is also chilled by a refrigeration system 7.

It will be appreciated that plain water enters the vessel 3 through the water supply 6 and that a head space 9 is pressurised by CO2 gas through the gas supply 5.

Typically, the water will be pumped into the vessel 3 by a diaphragm pump 8. This pump 8 uses the CO2 gas pressure applied alternatively either side of the diaphragm to pump water. Thus, the water supply 6 pressure P2 = P1 + Pw where P1 = CO2 gas pressure and Pw = mains water pressure.

As the vessel 3 is essentially closed it will be appreciated that carbonator pressure P3 builds until P2 = P3. Thus, water input to the vessel 3 stops with the head space 9 full of pressurised CO2 gas.

As the vessel 3 and water 2 are cooled by the refrigeration systems 7 the water 2 absorbs CO2 gas from the head space 9. Thus, P3 falls and more water is drawn into the vessel 3. This cycle is repeated until the vessel is completely full of water 2 and so all CO2 gas has been absorbed. The vessel 3 is then full of carbonated water to provide the reservoir required.

Essentially the vessel's head space 9 is filled with CO2 gas which has displaced the dispensed carbonated water. After refilling (through gradual 'cycles') that 'displacement' pressure volume value is taken into an equivalent volume of water. This principle determines the level of CO2 volumes absorbed.

It will be appreciated that during the early carbonisation cycles it is advantageous to maximise the CO2 gas head space 9 in order to promote carbonisation.

Thus, the water supply 6 to the vessel 3 generally has a restrictor tube so that CO2 gas enters to fill the vessel more rapidly that still water.

The use of a restrictor tube also has advantages when carbonated water 2 is dispensed through outlet 4.

Without a restrictor tube the pump 8 would rapidly fill the vessel 3 so only limited volumes of CO2 gas can be absorbed during each carbonisation cycle. The restrictor tube ensures the vessel 3 is mostly filled with fresh CO2 gas at a pressure of P1. It will be appreciated the carbonisation cycles are again repeated until the head space 9 is reduced to a negligible volume.

Figure 2 illustrates a typical performance profile for a carbonator in accordance with the present invention. Figure 2 illustrates graphically the head space CO2 pressure (1), the percentage of the vessel filled (2) and the volume of CO2 gas in vessel water (3) all against dispense cycle period.

Initially, when the vessel 2 is empty (A), the head space CO2 pressure (1) is 50 psi, that is to say the pressure of the head gas. It will be appreciated that as the vessel is filled (B), the head space pressure (1) rises as does the percentage of the vessel filled (2), the volume of CO2 in the water only shows a marginal level (3). As carbonated water is dispensed from the vessel (C), the head pressure (1) along with the volume of the vessel filled (2) rapidly decreases but the volume of CO2 in the water left in the vessel remains substantially static (3). As the vessel is refilled (D), the head pressure (1) and percentage of the vessel filled (2) show a more gradual increase along with the volumes of CO2 in the water. At a stand-by conditional (E), carbonation cycling is occurring, the head space pressure (1) and vessel percentage full (2) maximising and the volume of CO2 in water is also maximising and is greater than at earlier stages. Upon further dispense (F), the head pressure (1) and vessel fill percentage (2) again rapidly decrease but upon this stage the CO2 (3) volume in the water again remains substantially stable. The vessel is again refilled (G), and the head pressure (1) and vessel percentage fill increase but the CO2 volumes in the water decrease until the carbonator again achieves the stand-by condition (not shown).

It will be appreciated that the present carbonator has no motor or water sensor control compared to conventional carbonators so reducing costs. Furthermore, the operating costs of the motor are removed.

Claims (5)

1. A method of carbonating water in a vessel, said method including feeding C02 gas under pressure into the vessel, feeding water under pressure into the same vessel until the water inlet pressure equals the pressure in the vessel, cooling the water in the vessel such that the water absorbs C02 gas thereby reducing the pressure in the vessel, and automatically supplying more CO2 gas and water to the vessel in response to said reduction in pressure.

2. A method as claimed in claim 1 including the step of restricting the supply of water to the carbonator such that C02 gas is preferentially admitted when carbonated water is dispensed.

3. A carbonator for carrying out the method of claims 1 and 2 including a vessel with a C02 gas supply and a water supply in pressure equilibrium, the water being cooled such that the water absorbs the C02 gas from a head space above the water surface to provide carbonated water in the vessel, the absorption of C02 gas disturbing the pressure equilibrium by reducing carbonation pressure in the vessel and so more water and C02 gas is drawn into the vessel until the head space is substantially eliminated.

4. A method of carbonating water as hereinbefore described with reference to the accompanying drawings.

5. Apparatus for carbonating water as hereinbefore described with reference to the accompanying drawings.