GB2442721A

GB2442721A - Injecting additional carbonating gas into a carbonated beverage downstream of the delivery valve

Info

Publication number: GB2442721A
Application number: GB0620291A
Authority: GB
Inventors: David Downham
Original assignee: Fortune Products Ltd
Current assignee: Fortune Products Ltd
Priority date: 2006-10-12
Filing date: 2006-10-12
Publication date: 2008-04-16
Anticipated expiration: 2026-10-12
Also published as: GB2442721B; GB0620291D0

Abstract

There is disclosed a beverage dispenser in which a carbonated beverage is dispensed through a delivery valve (2b - 5b) into a delivery tube (2c - 5c) leading to a spigot. A carbonating gas is injected via a gas injection line (12a - 12d) into the delivery tube immediately downstream of the delivery valve during dispensing of the beverage. The carbonating gas may be injected continuously during dispensing of the beverage, or an intermittent cyclic injection of gas may be provided. The gas and beverage flow controls may be arranged so that carbonating gas injection is commenced before dispensing of the beverage commences.

Description

BEVERAGE DISPENSER

The present invention relates to beverage dispensers, and is particularly concerned with multi-flavour beverage dispensers for use in retail outlets, for dispensing drinks such as cola, soda water, or other carbonated soft drinks.

It has become common in bars and restaurants for soft drinks to be dispensed from a dispensing head mounted at one end of a flexible hose which is fixed to a structure such as a bar or counter top. The dispensing head typically dispenses a plurality of different beverages, which are supplied to the head through individual supply tubes within the flexible hose. These supply tubes are connected to reservoirs of the various beverages, which are stored in bulk at a remote location.

The dispenser head is a complicated structure incorporated valves for supplying either premixed drinks, or for mixing soda water and syrups to produce drinks of differing flavours. In order to ensure that the drinks are delivered at the correct temperature, it is customary to circulate refrigerated soda water to the dispensing head, by providing a supply tube for the refrigerated soda water and a return tube *1 extending back down the flexible hose.

This arrangement makes the flexible hose bulky since it has to accommodate the return tube for the recirculating soda water. However, if the soda water is not recirculated through the flexible tube, then liquid in the flexible tube will warm up during periods of non-use of the dispenser, resulting in uncooled liquid being dispensed at the start of the next dispensing operation.

A further disadvantage of the existing arrangement is that the dispenser head is a complicated structure including valves, control buttons and internal galleries. The dispenser head is also the structure most likely to be dropped or mishandled by the operator resulting in damage to the dispenser head.

The present invention has as one objective the provision of a carbonated beverage dispenser installation in which the carbonation level of the dispensed beverage is increased.

A further objective of the invention is to provide a dispensing arrangement for soft drinks in which dispensing of uncooled liquid is avoided.

A further objective of the invention is to provide a dispensing arrangement for soft drinks in which a dispensing head is carried at the distal end of a flexible hose of increased flexibility, while avoiding the problem of initially dispensing uncooled liquid after a period of non-use.

Another objective of the invention is to provide a control arrangement for a beverage dispenser, which controls the dispensing of carbonated beverages so as to inject carbonating gas while the beverage is being dispensed, to increase the carbonation level in the beverage.

Another objective of the invention is to provide a control arrangement for a beverage dispenser, which controls the dispensing of beverages and the clearing of liquid from a delivery tube downstream of a dispensing valve after each dispensing operation.

According to a first aspect of the invention, there is provided a beverage dispensing installation comprising a reservoir for a carbonated beverage, a supply duct for a supplying the carbonated beverage from the reservoir to a delivery valve, a delivery tube for conducting the carbonated beverage from the delivery valve to a delivery spigot in a delivery head, and control means for selectively opening and closing the delivery valve, and further comprising a reservoir for a carbonating gas, a gas supply line for

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supplying carbonating gas from the reservoir to a gas control valve, and a gas injection line for supplying carbonating gas from the gas control valve to a gas injection port provided in the delivery tube downstream of the delivery valve, and wherein the control means is adapted to open the gas control valve to deliver carbonating gas into the delivery tube while the delivery valve delivers carbonated beverage to the delivery tube. The decrease in carbonation level caused by the sudden pressure drop across the delivery valve is mitigated by the carbonation gas injected into the delivery tube dissolving in the beverage.

In one embodiment, the beverage dispensing installation may be operated to perform carbonating gas injection while a carbonated beverage is being dispensed, and to perform a gas injection for purging liquid from the delivery tube after a beverage dispensing operation.

According to a second aspect of the invention, there is provided a method and apparatus for dispensing a beverage, in which beverage components are selectively admitted to delivery tubes by opening and closing delivery valves, and wherein a purging gas is introduced into the delivery tube after closure of r the delivery valve to expel liquid from the delivery tube. The delivery tube is thus maintained "dry" between dispensing operations, avoiding the problem of warm liquid being dispensed at the start of a subsequent dispensing operation, due to liquid in the delivery tube warming up to room temperature between dispensing operations.

According to a third aspect of the invention there is provided an improved dispensing control arrangement for a beverage dispenser wherein carbonating gas injection is performed continuously or intermittently while a carbonated beverage is being dispensed.

A fourth aspect of the invention provides a control arrangement for a beverage dispenser operable to cause a purging gas to be introduced into the delivery tube of the beverage dispenser after each dispensing operation. The dispensing control arrangement may provide for beverages to be dispensed on a "free-flow" or on a "portion control" basis.

A fifth aspect of the invention provides a gas injection arrangement wherein a carbonating or purging gas injection line extends along the lumen of a beverage delivery tube, the gas injection line having gas injection openings spaced along its length. p

Embodiments of the invention will now be described in detail with reference to the accompanying drawings, in which: Figure 1 is a schematic view of a beverage dispensing arrangement according to a first embodiment of the present invention; Figure 2 schematically shows the control circuitry of the dispenser of Figure 1.

Figure 3 is a schematic diagram showing the layout of valves and tubes in an alternative arrangement of a pre-mix dispenser; Figure 4 illustrates schematically shows the control circuitry of the dispenser of Figure 3; Figure 5 illustrates a further alternative arrangement for a post-mix dispenser; Figure 6 is a schematic sectional view, to an enlarged scale, showing the structure of the gas injection line; and Figure 7 illustrates a further alternative arrangement for a post-mix dispenser, as a fixed installation rather than a hand-held dispenser.

Referring now to the Figures, Figure 1 is a schematic view of a beverage dispensing arrangement in which a refrigerated enclosure 1 houses four reservoir tanks 2, 3, 4 and 5. The reservoir tanks have ( respective outlet lines 2a, 3a, 4a, 5a which are lead through an insulated flexible duct 6 to respective delivery valves to 2b, 3b, 4b and Sb. From the delivery valves, delivery tubes 2c, 3c, 4c and 5c lead through a flexible sheath 7 to a delivery head 8. The delivery head 8 includes four control buttons 9a, 9b, 9c and 9d, whose purpose will be described later. At the end of each of the delivery tubes 2c, 3c, 4c and 5c is a delivery spigot 2d, 3d, 4d and 5d, incorporating a non-return valve which is resiliently biased towards a closed position, but will open when pressure in the respective delivery tube 2c, 3c, 4c or Sc increases beyond a predetermined limit. The resiliently biased valve in the delivery spigot provides a slight back-pressure to the delivery valves which improves their operation, and the small pressure drop across the spigot reduces foaming in the dispensed beverage.

A high-pressure gas reservoir 9 supplies gas through a gas supply line 10 to a gas control valve 11. When the gas control valve 11 is opened, high pressure gas is supplied through respective gas injection lines 12a, 12b, 12c and 12d to the delivery tubes 2a, 2b, 2c and 2d, at points immediately downstream of their respective delivery valves 2b, 3b, ( 4b and Sb. In the illustrated embodiment, the gas reservoir 9 contains carbon dioxide at high pressure, and through a carbonation supply line 13 provides carbonating gas to the reservoir tank 2, in which is contained carbonated water.

In the illustrated embodiment of Figure 1, refrigerated carbonated water is drawn from reservoir tank 2 by a recirculatjon pump 14, and is pumped through the outlet line 2a, which passes through the insulated duct 6. At the distal end of the insulated duct 6, a carbonated water recirculatjon line 15 is branched off the outlet line 2a, and returns the carbonated water to the reservoir tank 2 when the delivery valve 2b is closed. This recirculation of cooled carbonated water within the insulated duct 6 ensures that the liquids within the outlet lines 3a, 4a and 5a remain cool.

In the embodiment illustrated in Figure 1, the delivery valves 2a to 5a and the gas control valve ii are electrically controlled, on the basis of signal inputs from the respective control buttons A to D on the delivery head 8.

Figure 2 illustrates the control circuitry of the beverage dispensing installation of Figure 1. The control circuitry comprises a delivery valve control 16, which detects an input from one of the control buttons A to D, and opens one or more delivery valve 2b to Sb associated with that control button, maintaining the delivery valve or valves open as long as a control button is held depressed. When the control button A to D is released, the delivery valve control circuit 16 closes the associated delivery valve or valves 2b to 5b, and sends a signal to a gas control circuit ii. The gas control circuit 17, on receiving the signal, initiates a timer circuit 18 which opens the gas control valve 11 for a predetermined time interval. At the end of the predetermined interval, gas control valve 11 is again closed.

In operation, the reservoir tank 2 is filled with carbonated water, and reservoir tanks 3, 4 and 5 are respectively filled with flavourings. For example, tank 3 may be filled with a sugar-free cola syrup, tank 4 may be filled with a fruit syrup, and tank 5 may be filled with a conventional cola syrup containing sugar. Control buttons A to D on the delivery head 8 are preferably marked to indicate the beverage which will be dispensed on pressing each respective button.

While the embodiment of Figure 1 comprises four ( reservoir tanks, one for carbonated water and three for non-carbonated beverage syrups, it will be understood that an installation only to supply one carbonated beverage, such as soda water or a single flavoured beverage, may be foreseen, in which only a single reservoir, outlet line 2a with recirculating cooling line 15, delivery valve 2b, delivery tube 2c and delivery spigot 2d is provided.

If button A is to dispense refrigerated carbonated water (soda water), then the delivery valve control circuit 16 will open delivery valve 2b when button A is pressed, and soda water will be delivered through valve 2b to the delivery tube 2c, and out of the delivery spigot 2d. The pressure of the soda water will exceed the pressure required to open the non-return valve in delivery spigot 2d. When button A is released, delivery valve 2b is closed and as the pressure in delivery tube 2c falls, the non return valve in the delivery spigot 2d also closes. In order to eliminate the liquid from the delivery tube 2b, the gas control circuit 17 then actuates the timer 18 to open the gas control valve 11 for a limited period, to inject pressurised gas into the delivery tubes 2c to 5c. The high-pressure gas drives the remaining liquid from the delivery tube 2c, opening the non return valve in the delivery spigot 2d and dispensing the liquid while it is still at the cooled temperature.

At the same time, high pressure gas purges the delivery tubes 3c to 5c, the gas being vented through 5 their respective delivery spigots.

If the user wishes to dispense a sugar-free cola drink, then the control button B is pressed. The delivery valve control circuit 16 then opens the delivery valve 2b and the delivery valve 2c so that cooled carbonated water is delivered from the spigot 2d and sugar-free cola syrup is delivered from the spigot 3d, to mix in the glass after delivery. The delivery valves 2b to 5b include flow control arrangements to ensure that the carbonated water and the respective flavouring are delivered together in appropriate proportions. When the control button B is released, the delivery valve control 16 closes the delivery valves 2b and 3b, and signals the gas control circuit 17 to activate the controller 18 and open the gas control valve 11 for a predetermined period. The injection of high-pressure gas into the delivery tubes causes any liquid remaining in the delivery tubes to be delivered through the respective delivery spigot, as described before.

In the manner similar to the operation controlled ( 12 --by the control button B, buttons C and D respectively cause the opening of delivery valve combinations 2b and 4b, and 2b and 5b, resulting in the simultaneous delivery of carbonated water and the appropriate flavouring.

As will be evident, the liquid dispensed by the dispenser head is drawn from liquid stored in the outlet lines 2a to 5a, which are contained within the insulated duct 6 (this duct being commonly referred to as a "python"). This liquid is maintained at the cooled temperature by the recirculation of soda water through the outlet line 2a and the recirculation line 15, driven by the recirculatjon pump 14. The reservoir tanks 3, 4 and 5 containing the flavouring syrups may be pressurised in order to deliver the syrup through the outlet lines when the respective delivery valves are opened, or may be provided with pumps or other delivery means to ensure that syrup is delivered at the required rate when the respective delivery valve is opened.

Since no liquid remains in the delivery tubes, which are outside the insulated duct or python after each dispensing operation, due to the purging of the delivery tubes by the pressurised gas, the liquid or liquids dispensed in each dispensing operation are drawn directly from the outlet lines 2a to 5a within the python, and are therefore cool.

Figure 3 illustrates an alternative arrangement for the delivery of purging gas to the delivery tubes 2c to 5c. In contrast to the arrangement shown in figure 1, where a single gas control valve ii delivered purging gas to all of the delivery tube 2c to 5c simultaneously, in the arrangement of figure 3 purging gas is delivered from a gas reservoir 9 to a gas manifold 19. The manifold 19 is connected via individual gas supply lines l0a, lob, lOc, lOd to respective gas control valves ha, lib, lic and lid.

Each of the gas control valves is then connected to one of the delivery tubes 2c to 5c, immediately downstream of its respective delivery valve 2b to Sb via a respective gas injection line 12a to 12d. The delivery head 8 is the same as has been described in relation to figure 1.

Figure 4 illustrates schematically the control circuitry for the dispenser of figure 3. The delivery valve control circuit 16 operates in a similar manner to that described in relation to the embodiment of Figures 1 and 2, in that when one of the control buttons A to D is pressed, the delivery valve control circuit 16 opens the delivery valve 2b to dispense 14 -carbonated water, and optionally also one of the delivery valves 3b, 4b and 5b to dispense a flavouring syrup to be mixed with the carbonated water. While the control button is pressed, the valves are opened to deliver a flow of liquid from the delivery head 8.

When the button is released, the delivery valve control circuit sends a signal to the gas control circuit 17. The signal indicates which of the delivery valves 2b to Sb has been opened, and the gas control circuit 17 then sends a signal to the timer circuit 18 instructing the opening of one or more of the respective gas control valves ha to lid, so that pressurised gas is admitted only to those delivery tubes 2c to 5c which have just been used to dispense liquid, in order to purge the liquid from those delivery tubes via their delivery spigots 2d to 5d.

When the gas control valves ha to lid are open, pressurised gas is delivered from the gas reservoir 9 via the gas manifold 19 to the gas supply lines iOa to hOd, and then through the open gas control valve ha to lid to the gas injection line 12a to 12d for injection into the delivery tubes 2c to 5c. The arrangement shown in figures 3 and 4 is more economical in its use of pressurised gas, since the gas is supplied only to delivery tubes which have been used, in contrast to the arrangement in figure 1 where all of the delivery tubes are purged each time any of them is used.

Figure 5 shows a further alternative arrangement of the beverage dispenser. In this arrangement, the insulated duct or python 6 contains as before an outlet line 2a and a recirculatjon line 15 for soda water, and outlet lines 3a, 4a and 5a for flavour syrups. The outlet line 2a for soda water is led to a delivery valve 2b, and then to a delivery tube 2c leading to the delivery head 8. The outlet line 3a is led to a delivery valve 3b, and the delivery tube 3c from the delivery valve 3b is then joined to the delivery tube 2c. The delivery tube 2c will therefore delivery either pure soda water, if delivery valve 2b is opened alone, or it will deliver a mixture of soda water and flavour syrup if valves 2b and 3b are opened simultaneously.

Outlet line 4a is led to a combined mixing and delivery valve 4b, which is supplied with soda water from the outlet line 2a. When the valve 4b is opened, a mixture of soda water and flavoured syrup is delivered to the delivery tube 4c and thence to the delivery head 8.

Similarly, outlet line 5a is led to a combined mixing and delivery valve 5b, which is also fed with soda water from the outlet line 2a. Opening the valve Sb delivers a mixture of flavoured syrup arid soda water to the delivery tube 5c. Preferably, the delivery valves 2b to 5b include metering means such as adjustable orifices to control the flow rates of the soda water and syrup to ensure the correct mixture ratio is delivered to the delivery tubes 2c to 5c.

In this arrangement, high pressure gas from a gas reservoir 9 is supplied to a gas manifold 19, and from the manifold 19 via gas supply lines iOa, bc and bod to respective gas control valves ha, hic and lid.

Gas control valve ha delivers gas via a gas injection line 12a to the delivery tubes 2c and 3c immediately downstream of their respective valves 2b and 3b. Gas control valves lic and lid respectively deliver gas through gas injection lines 12c and i2d to the delivery tubes 4c and Sc immediately downstream of the mixing and delivery valves 4b and 5b, respectively.

The arrangement shown in figure 5 allows the flexible sheath 7 which surrounds the delivery tubes 2c, 4c and Sc to be reduced in thickness and thus increased in flexibility, since the flexible sheath 7 has only to accommodate three delivery tubes rather than four as in the previous embodiment.

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The control circuitry for the embodiment illustrated in figure 5 is similar to that illustrated in figure 4, except that the gas control valve llb shown in figure 4 is omitted. The delivery valve control circuit 16 is arranged so that when control button A is pressed, the delivery valve 2b is opened and pure soda water is delivered through delivery tube 2c. When control button B is pressed, delivery valves 2b and 3b are opened simultaneously, and a mixture of soda water are flavoured syrup is delivered through delivery tube 2c.

As before, when the control button A or B is released, the delivery valve control circuit 16 signals the gas control circuit 17, which initiates the timer circuit 18 to supply gas through the gas control valve l].a, to purge any liquid from the delivery tube 2c.

In the installations illustrated in Figures 1, 3 and 5, the gas injection lines 12a to l2d are simply joined to the beverage dispensing lines 2c to 5c at a "T1' joint, to deliver the purging gas to the beverage dispensing lines immediately downstream of the respective delivery valves 2b to 5b.

Figure 6 illustrates a preferred embodiment of the gas injection line 12. In the figure, delivery

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valve 2b and delivery tube 2c are shown, with gas control valve lib and gas injection line 12b. The gas injection line 12b extends from the gas control valve lib, through the wall of the delivery tube 2c, and then a portion 20 of the gas injection line extends along the delivery 2c within the lumen of the delivery tube. The portion 20 of the gas injection line has openings 21 spaced along its length, to deliver gas from within the portion 20 to the lumen of the delivery tube 2c. Preferably, the portion 20 of the gas injection line extends for a substantial distance along the delivery tube. In a typical installation, the portion 20 may be up to one metre in length, with the openings 21 spaced at intervals of approximately 100mm. In an typical installation, the delivery tube 2c has an internal diameter of approximately 5mm, and the gas injection line 12b has an external diameter of approximately 3mm. By extending the gas injection line 12b along the length of the delivery tube 2c, internal wetting of the delivery tube by the delivered liquid is reduced, and a more complete purging of the liquid from the delivery tube is ensured.

While the embodiments so far described have been installations in which the delivery head is mounted to a flexible sheath 7, an alternative arrangement illustrated in figure 7 includes a fixed dispensing stand instead of the sheath 7 and delivery head 8. In the embodiment shown in figure 7, the pipework and flow control up to and including the delivery valves 2b to 5b and the gas control valves ha to lid are as illustrated in relation to the embodiment of figure 3, and control is effected in the same way as has been described in relation to figure 4. The delivery tubes 2c to 5c are led not to a delivery head 8 as shown in figure 3, but to a delivery stand 22 comprising an upstanding pillar 23, a top surface 24 including control buttons A to D, and delivery spigots 2d to 5d including non-return valves as previously described.

At the base of the pillar 23 a clamping arrangement 25 is provided for fixing the pillar to an edge of a countertop 26, by clamping the countertop against an abutment 27 using a clamping screw 28.

In the fixed arrangement shown in figure 7, a drip tray may be provided to catch any drips from the delivery spigots 2d to Sd.

The control arrangements for the "fixed" embodiment of figure 7 may differ slightly from those of the previous embodiments, in that the gas control circuit 17 may be arranged to purge the delivery tubes 2c to 5c at predetermined intervals, in order to ensure that no liquid is present downstream of the delivery valves 2b to 5b. Also, in the fixed" embodiment, the control buttons A to D need not be placed on top of the pillar 23, but may be positioned on or adjacent to the base of the pillar, or in a separate control panel.

While in the described embodiments carbon dioxide is used as the purging gas, it is contemplated that other inert gases such as nitrogen may be used, or compressed air may be used as a purging gas. In alternative embodiments, pipe cleaning fluids may be injected into the delivery tubes 2c to 5c using the gas supply lines 10, gas control valves 11 and gas injection lines 12, provided that the gas control valves 11 are suitably constructed to handle both liquids and gases. In the embodiment illustrated in figure 7, automatic cleaning of the delivery tubes may be provided for, using the gas control circuitry and additional cleaning fluid supply means to intermittently inject cleaning fluid through the gas injection lines, and thereafter purge the delivery tubes with pressurised gas. Such a control arrangement may, for example, be automated and controlled by a clock circuit so that the delivery tubes are cleaned automatically after a period of use of the dispenser arrangement, such as after closing time of the establishment in which the beverage dispenser is installed. A provision for manual cleaning may be made, providing an input means such as a control button to initiate a cleaning sequence in which cleaning fluid is injected into the delivery tubes to fill them, and after a predetermined period pressurised gas is injected into the delivery tubes to expel the cleaning fluid.

In the embodiments described above, control of the dispensing of beverages has been on a "free-flow" basis, in that beverage is dispensed for as long as the control button is held depressed. It is also foreseen that the delivery valve control circuit 16 may be arranged to provide portion control, for example by arranging the delivery valve control circuit 16 so that when a one of the control buttons is depressed for a short time, or "tapped", then a predetermined amount of beverage is dispensed. This may be achieved by causing the delivery valve control circuit 16 to open the relevant delivery valves for a predetermined time, in response to a "tap" of the control button. The control circuitry may be operable in a "dispense" mode for normal operation, and in a "teaching" mode, for setting the amount of beverage to 22 -be dispensed as a portion. The control circuitry may select the "teaching" mode or the "dispense" mode in response to a control signal from a selector input, or from a predetermined combination of control buttons being pressed together.

In the teaching mode, the control button may be held depressed until the required amount of beverage has been dispensed, and the control button is then released. The delivery valve control circuitry will rnemorise the time for which the button was held depressed. When the control circuitry is again in the "dispense" mode, a "tap" on the control button will cause the delivery valve control circuit to open the delivery valve for the memorised time interval.

In addition to the control buttons A to D, the dispenser head may be provided with two or more further buttons M and L indicative of different portion sizes. The control circuitry may, for example, be arranged so that when control button A is pressed on its own, a "small" portion is dispensed.

When the control button A his pressed in combination with the M button, a "medium" portion may be dispensed, and when the control button A his pressed in combination with the L button "large" portion may be dispensed.

The reservoirs for flavouring syrups described in the above embodiments are maintained refrigerated in the cooled enclosure 1. It is however foreseen that the flavouring syrups may be stored at room temperature, and may pass through a chilling unit before entering the delivery tube and the python.

In a further alternative mode of operating the beverage dispenser, it is foreseen that carbonating gas (C02) may be injected into the delivery tube for the carbonated liquid (soda water) via its respective gas injection line during the dispensing of a beverage, in order to maintain a higher level of carbonation in the liquid then is the case when liquid is simply dispensed from the beverage dispenser without additional gas injection.

This alternative mode of operation may be used with the arrangement illustrated in Figure 3, in which CO2 (used as a purging gas) is delivered from a gas reservoir 9 to a gas manifold 19 connected via individual gas supply lines].Oa, lob, lOc, lOd to respective gas control valves].la, lib, lic and lid.

Each of the gas control valves is connected to one of the delivery tubes 2c to Sc, immediately downstream of its respective delivery valve 2b to 5b via a respective gas injection line 12a to 12th The delivery head 8 is the same as has been described in relation to figure 1. The control circuitry for the dispenser operates in a similar manner to

that described in relation to the embodiment of Figures 1 and 2, in that when one of the control buttons A to D is pressed, the delivery valve control circuit 16 opens the delivery valve 2b to dispense carbonated water, and optionally also one of the delivery valves 3b, 4b and 5b to dispense a flavouring syrup to be mixed with the carbonated water. While the control button is pressed, the valves are opened to deliver a flow of liquid from the delivery head 8. In this embodiment, however, the delivery valve control circuit 16 also sends a signal to the gas control circuit 17 to open the appropriate gas control valve ha to inject carbonating gas (C02) into the carbonated liquid being dispensed.

The gas injection may be started immediately liquid flow is established by opening the delivery valve 2b, and may continue as a continuous injection of gas during delivery of the liquid. Alternatively, gas injection may be made intermittently while the liquid flows. In the case of an intermittent delivery of gas, gas may be injected for a first predetermined interval and then the gas supply turned off for a second interval, and then this cycle may be repeated.

The first and second intervals may be of equal length.

In a yet further embodiment, the delivery valve control circuit 16 and the gas control circuit 17 may be arranged so that when one of the buttons A to D is pressed, gas is first injected into the appropriate delivery tube to pressurise the tube, prior to opening the delivery valve 2b to dispense carbonated water.

Gas injection may then continue, either continuously or intermittently, during dispensing of the carbonated liquid.

When the button is released, the delivery valve control circuit operates to close the delivery valve 2b and any of the delivery valves 3b, 4b and 5b which have been open. The delivery valve control circuit 16 may then send a signal as before to the gas control circuit 17 to indicate that liquid dispensing has ceased. The gas control circuit 17 then sends a signal to the timer circuit 18 so that the respective gas control valve ha to lid continues to admit gas to the delivery tube or tubes 2c to 5c which have just been used to dispense liquid, in order to purge the liquid from the delivery tubes via their respective delivery spigots 2d to 5d.

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The pressure at which gas is injected into the delivery tube during dispensing of carbonated liquid is arranged to be slightly higher than the dynamic pressure of the liquid flowing past the point of gas injection. Typically, if the dynamic pressure of the liquid at the injection point is 20psi (1.378 bar), then the gas is injected at a pressure of from 20 up to 25psi (1.378 to 1.722 bar). If purging of the delivery tube is performed after the liquid delivery has ceased, the gas injection pressure may be varied after the end of the liquid delivery, either to purge the delivery tube using gas at a pressure higher or lower than the pressure used during liquid delivery for injecting the gas. Gas purging of the delivery tube may also be performed using gas at the same pressure as is used during liquid delivery for injecting the gas.

Although gas injection during liquid dispensing is described above in relation to the apparatus shown in Figure 3, it is to be understood that the beverage dispenser illustrated in Figures 1, 5 or 7 may also be modified to provide gas injection into the carbonated liquid during the dispensing of a beverage. )

Claims

Claims: 1. A carbonated beverage dispensing installation comprising: a

reservoir for a carbonated beverage; a supply duct for a supplying the carbonated beverage from the reservoir to a delivery valve; a delivery tube for conducting the carbonated beverage from the delivery valve to a delivery spigot in a delivery head; and control means for selectively opening and closing the delivery valve; and further comprising: a reservoir for a carbonating gas; a gas supply line for supplying carbonating gas from the reservoir to a gas control valve; a gas injection line for supplying carbonating gas from the gas control valve to a gas injection port provided in the delivery tube downstream of the delivery valve; and wherein the control means is adapted to open the gas control valve to deliver carbonating gas into the delivery tube while the delivery valve delivers carbonated beverage to the delivery tube.

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2. A beverage dispensing installation according to claim 1, further comprising one or more further reservoirs adapted to contain non-carbonated beverage components, each having a respective further beverage component supply duct, delivery valve, delivery tube and spigot, and wherein the control means is adapted to open the delivery valve for the carbonated beverage and a further delivery valve for a non-carbonated beverage component simultaneously.
3. A beverage dispensing installation according to claim 1 or claim 2, wherein the control means is operable to open the gas control valve for a predetermined period before opening of the delivery valve for the carbonated beverage.
4. A beverage dispensing installation according to any preceding claim, wherein the control means is operable to open and close the gas control valve cyclically during the period for which the delivery valve for the carbonated beverage is open.
5. A beverage dispensing installation according to any preceding claim, wherein the gas injection line

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extends through the wall of the delivery tube at a point immediately downstream of its dispensing valve, and extends in the downstream direction along the lumen of the beverage delivery tube, the gas injection line having gas injection openings spaced along that part of its length which is within the beverage delivery tube.
6. A method of dispensing a beverage, in which a carbonated beverage component is selectively admitted to a delivery tube by opening and closing a delivery valve, and wherein a carbonating gas is introduced into the delivery tube while the delivery valve is open.
7. A method according to claim 6, wherein a gas control valve is opened to introduce carbonating gas into the delivery tube simultaneously with the opening of the delivery valve.
8. A method according to claim 6, wherein a gas control valve is opened to introduce carbonating gas into the delivery tube to pressurise the delivery tube shortly before the opening of the delivery valve.

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9. A method according to claim 6, wherein a gas control valve is opened arid closed cyclically to introduce carbonating gas into the delivery tube intermittently during the period for which the delivery valve is open.
10. A dispensing control arrangement for a beverage dispenser in which a carbonated beverage is supplied from a reservoir via a supply duct to a delivery valve, and wherein the beverage is conducted via a delivery tube from the delivery valve to a delivery spigot in a delivery head, the beverage dispenser further comprising a reservoir for carbonating gas, a gas supply line for supplying gas from the reservoir to a gas control valve, and a gas injection line for supplying gas from the gas control valve to a gas injection port provided in the delivery tube downstream of the delivery valve; and wherein the dispensing control arrangement comprises: input means; control means for selectively opening and closing the delivery valve and the gas control valve, the control means being adapted to open and close the delivery valve in response to signals from the input ) means, and to open the gas control valve while the delivery valve is open.
11. A dispensing control arrangement according to claim 10, wherein the input means is a control button having a "pressed" and a "released" condition, and wherein the control means causes the delivery valve to be open when the button is in the "pressed" condition, and closed when the button is in the "released" condition.
12. A dispensing control arrangement according to claim 10, wherein the input means is a control button having a pressed and a released condition, and wherein the control means causes the delivery valve to open for a predetermined time interval when the control button is moved from its released to its pressed condition.
13. A dispensing control arrangement according to claim 12, wherein the control means has an operating mode and a learning mode, and wherein in the learning mode the control means causes the delivery valve to be open when the button is pressed, and closed when the button is released, and the control means is adapted to store in a memory information relating to the length of time for which the delivery valve is open; and wherein in the operating mode the control means causes the delivery valve to open for a length of time corresponding to the stored information when the control button is moved from its released to its pressed condition.