GB2190853A - Apparatus for dissolving gas in liquids - Google Patents

Abstract

An apparatus for dissolving a gas in a liquid, e.g. in the carbonation of wine, is provided which comprises a vessel for dissolving a gas in a liquid comprising an upper chamber (25) provided both with means (2) for supplying the gas thereto and a spray nozzle inlet (24) for supplying the liquid thereto, and a lower chamber (26) opening upwardly into the bottom of the upper chamber (25) through an aperture (28), the aperture being appreciably smaller than the cross-sectional size of the upper chamber (25) and/or the said lower chamber (26) having a cross-sectional size appreciably smaller than the cross-sectional size of the upper chamber (25). <IMAGE>

Description

SPECIFICATION Apparatus for dissolving gases in liquids This invention relates two an apparatusfordissolving gases in liquids which is adapted to dispense predetermined volumes of the resulting solution on a repetitive basis. Although the apparatus has application to a wide number of gas/liquid combinations, the preferred application of the invention is to the carbonation of wine. A new design of gas/liquid dissolving vessel (e.g. a carbonator) is also included.

In the past, the carbonation of still wine has involved the storage and distribution of wine under carbonation in pressurised containers. Carbonated wine was simply dispensed from these containers into the glass atthe point of sale. The actual carbonation of the wine was carried out bythe supplier inside a bonded warehouse. Such a system has not been commercially successful as a result of high costs involved in pressurised containers and theirtransportation. In addition to this it is, of course, known to produce carbonated soft drinks using post-mix dispense systems. In such cases, a flavour concentrate is mixed with carbonated water in the required proportions, either by the consumer in the glass or in a dispense valve system.

The development of the present gas/liquid dissolution system was simulated by a desire to provide an apparatus which would be capable of carbonating a still wine atthesale outlet, wherever that might be, in an accurate manner. Such an apparatus would avoid the necessity for expensive storage vessels and theirtransport. Such carbonated wine fall underthe category of aerated sparkling wine and used to be subjectto certain EEC regulations. In particular, these regulations (see Official Journal ofthe European Communities, 5th March 1979, L54 Volume 22 page No.L54/32) used to stipulate that the carbon dioxide content ofthe dispensed carbonated wine must not exceed a level which corresponds to the wine having an axcess carbon dioxide pressure of 3 barwhen art a temperature of 20"C in a closed container. However, maximum customer appear dictates that a carbonated wine when dispensed should have a relatively high carbon dioxide content. In any event, there is a need for a system which will dispense carbonated wine from a source of still wine but which atthe same time ensures that the carbon dioxide content ofthe dispensed wine is high and accurately determined. Furthermore, there is, however, no known drinks dispense system in which uncarbonated wine passes through e.g. a spray injection type carbonatorforthe purpose of being carbonated.

The present invention provides an apparatus for dissolving a gas in a liquid and repeatedly dispensing a fixed volume ofthe resulting solution, comprising a vessel for mixing the liquid and gas, meansforsupplyingthe liquid tothevessel, means forsupplyingthegastothevessel,meansfor determining the liquid level in the vessel, means connected to the liquid level determining means and responsive thereto for activating liquid supply to the vessel if the liquid level isbelowafirst predetermined level so asto raise the liquid level to the first predetermined level but no higher, means for dispensing the resulting solution from the vessel including an outlet valve having open and closed positions, and means connected to the liquid level determining means for adjusting the outletvalveto the open position when thevessel liquid level is at the first predetermined level and for adjusting the outlet valve to the closed position when the vessel liquid level reaches a lower and second predetermined level, the volume ofthe vessel between the first and second predetermined levels being the fixed volume.

The factors which affect the level of carbonation in any conventional carbonating system are: Carbonation Temperature The temperature of the liquid when it is contacted with carbon dioxide in the carbonator. As temperature decreases the level of dissolved carbon dioxide increases.

Carbonation Pressure The pressure of carbon dioxide in contact with the liquid in the carbonator. At any temperature, as carbonation pressure increases the level of dissolved carbon dioxide increases.

Gas-Liquid Contact Time Thetimethatthe liquid and carbon dioxide are in contact with each other in the carbonator. This is the carbonator residence time. When a spray injection type carbonator is operating with a continuous liquid feed in and out of the unit, the level ofcarbonation achieved is between 50% and 75% of the equilibrium value at the carbonation temperature and pressure being used. When thistype ofcarbonatoris usedto feed liquid directly to a dispense system the flow throughthecarbonatorwill be intermittent.In thins case liquid is carbonated to between 50% and 75% of the equilibrium value while liquid is being dispensed, but during the time interval between one dispense and the next, when there is no flow, the liquid which isresidentinthecarbonatorcontinues to absorb carbon dioxide and approaches the equilibrium value. The carbon dioxide level ofthe liquid which is dispensed from a conventional carbonation system is therefore variable, and dependent on the time interval between one dispense and the next. In addition, on dispensing the carbonated liquid to a glass the liquid undergoes a rapid reduction in pressure. The effect ofthis pressure reduction isforthe dissolved carbon dioxideto leave the liquid phase and return to its gaseous state.

The apparatus of the present invention is designed particularly to deal with variable carbonation levels (or levels of solution ofthe gas in the liquid) and, in some embodiments, to deal with the problem of rapid reduction in pressure as the carbonated liquid passes from the apparatus to a glass (in the case of carbonated wine). As indicated the amount of gas which passes into solution depends upon a number offactors. In the case of the carbonation of still wine, pressure,temperature, alcohol content, sugar content and pH ofthewine are most important.A typical carbonation pressure for still wine might be from 2 to 5 bar, the carbonation temperature might be from 2into 15"C and the resulting carbonation level might be from 2 g litre to 8 g/litre, all depending upon the nature of the original still wine product which is being carbonated.

The Official Journal ofthe European Communities of 14th May 1982, No. L133/78, deals with the question of carbonation of wines and the measurement of degree of carbonation. This reference also sets out the relationship between the various factors, e.g. the quantity of carbon dioxide contained in a sparkling wine, in grams of carbon dioxide per litre of wine, is given by the expression 1.977(1 + 0.987 P) (0.86 - 0.01 A) (1 - 0.00144 S); where: P = the excess pressure of carbon dioxide in the vessel expressed in bars at 20"C, A = the alcoholmetrictitre at 20"C ofthewine, and S = the sugar content of the wine in grams per litre.

In the present apparatus, a suitable outlet valve would be a solenoid controlled valve. In addition, a manually operated dispensing valve may be incorporated downstream of the outlet valve, which dispensing valve can optionally be contained within a cowl together with a dispense signalling switch.

Usually, a conduit is provided for carrying gas/liquid solution to the dispensing valve from the vessel where the solution is formed. This conduit may be provided with a flow regulating device and, downstream of the flow regulating device, means for cooling material passing through the conduit before it reaches the dispensing valve. The advantage of this system is that it avoids the problem noted above of substantial pressure reduction in dispensing a carbonated wine to the glass. Thus, in conventional carbonated drinks dispense systems, a flow regulating valve,which is necessary to control the rate atwhich a glass is filled, is incorporated into the actual dispense valve. Under these circumstances the carbonated liquid experiences a rapid reduction of pressure as itflows into the glass.The combination of rapid pressure reduction and turbulence as the liquid flows through the valve, causes dissolved carbon dioxide to be released in the form of small bubbles. This results in the loss of a large proportion ofthe carbon dioxide which was dissolved in the carbonator. In contrast, the preferred embodiments ofthe present invention use a flow regulating device which is separate from the dispense valve and located in pipe work between the vessel carbonator and the means for cooling material passing through the conduit to the dispensing valve. Thus, carbon dioxide released as a result ofthe reduction in pressure as the liquid flows through the regulating device is maintained in contactwiththe liquid as it passesthroughthe cooling means.This allowsia large proportion of released carbon dioxide to redissolve and thus the overall loss of carbon dioxide during the dispensing operation is considerably reduced compared to prior art systems. The flow regulating device may be a length of smooth small bore tubing built into the conduit. This is a very efficient means of regulating flow with minimum loss of gas. Alternatively, the device may be a valve.

The cooling means in the dispensing conduit may comprise a portion of the conduit formed as a cooling coil and passing through a refrigerated enclosure. When the flow regulating device is smooth small bore tubing this mayform part or all of the cooling coil. Of course, it is also preferred thatthe means for supplying liquid to the vessel for producing the gas-liquid solution includes means for cooling the liquid and this latter means may also be a cooling coil passing through the same refrigerated enclosure. The refrigerated enclosure is preferably thermostatically controlled and, ideally, has a temperature sensor positioned therein associated with means for preventing operation of the apparatus orfor switching off power supply to the refrigeration unit ofthe enclosure when the temperature in the enclosure drops below a preset value.It is preferred that the means for preventing operation ofthe apparatus includes means for preventing the supply of liquid to the vessel if dispensing of solution has not yet started and for preventing the outlet valve from adopting the open position or for closing the outlet valve if dispensing of solution has started. Preferably, the means for supplying liquid to the vessel includes a pump, the operation ofwhich pump is prevented by operation ofthe meansfor preventing the supplyof liquidto the vessel. Such atemperature monitoring system is a means by which carbonation may be strictly controlled and no such system is in operation in any existing apparatus or is suggested in the art.

Afurther preferred feature of the invention is that the meansforsupplying the gas (carbon dioxide, for example) to the vessel includes means for venting gas in the vessel to atmosphere. Thus, it is preferred that the apparatus of the present invention includes means for ensuring that if the volume of solution dispensed is less than the volume of the vessel between the first and second predetermined levels, the supply of gas to the vessel is ended and the gas in the vessel is vented to atmosphere via the venting means following a pre-set period oftime.

Furthermore, the vessel may be equipped with a pressure release valve adapted to open if gas pressure therein exceeds a predetermined value.

The gas venting means and the pressure release means valve may, of course, be the same structure.

Thus, in the most preferred embodiments ofthe invention, the invention provides an apparatus in which the volume of liquid (e.g. still wine) is strictly controlled and fixed volumes repeatedly dispensible, the temperature and pressure in the solution-forming vessel are strictly controlled, and the unusual position oftheflow regulating device before a secondary cooling means such as a cooling coil, ensures the minimum loss of gas from solution at the point of dispensing. The present apparatus permits the sequencing of carbonation and dispensing operations in a wine carbonation system to be such that only a small and consistent volume of liquid remains in the vessel/carbonator between use ofthe equipment.This achievement is entirely dependentuponthelinkingofthepredetermined levels in the vessel (high and low levels) to the opening and closing of the vessel outlet valve.

The invention also includes a vessel suitable for use in the present apparatus comprising an upper chamber provided both with means for supplying the gas thereto and a spray nozzle inletforsupplying theliquidthereto,anda lowerchamberopening upwardly into the bottom ofthe upper chamber through an aperturewhich is appreciably smaller than the cross-sectional size ofthe upper chamber.

In another aspect the invention provides a vessel for dissolving a gas in a liquid comprising an upper chamber provided both with means for supplying the gas thereto and a spray nozzle inlet for supplying the liquid thereto, and a lowerchamberopening upwardlyintothe bottom oftheupperchamberand having a cross-sectional size appreciably smaller than the cross-sectional size ofthe upper chamber.

The aforesaid two aspects of the invention provide a wholly new concept in, forexample, carbonator.

Of course, although the present invention is described with reference to a wine carbonation system, it is envisaged that the apparatus can be applied, with such consequential modifications as are apparent to the skilled man, to any gas/liquid dissolving system. Thus, one possible use of the apparatus of the present invention is for chlorinating and dispensing water, i.e. as a water purification unit.

The invention will now be further described and illustrated (but not necessarily limited) by reference to the accompanying drawings, in which: Figure lisa schematic diagram of a wine carbonation and dispense system in accordance with the invention; Figures2A, 2B, 2C and 2D are circuit diagrams for the control of a system as shown in Figure 1; Figure 3 is a flow sequence showing the operation of a system as illustrated in Figure 1; and Figure 4 shows a newcarbonatorinaccordance with the invention.

The apparatus in accordance with the invention shown generally by reference numeral (1), comprises a supply of carbon dioxide (2) leading via a valve (3) to a carbonator or gas/l iquid mixing vessel (4). Also leading into vessel (4) is a conduit(5) conveying still wine from a supply (6). In its passage from supply (6) to vessel (4), the still wine passes through a feed pump (7) and a primary cooling coil (8). Coil (8) is immersed in a cooling bath (9) which is powered by a conventional refrigeration unit (10).

Leading from vessel (4) via an outlet solenoid valve (14) is a dispensing conduit (11 ) which incorporates a flow regulating device (12).

Downstream of device (12) is a secondary cooling coil (13)which is immersed in the same cooling bath (9) as coil (8). Conduit (11) then leads to a manually-operated dispensing valve (22) for dispensing of carbonated liquid into receiver (15) (e.g. a glass).

Vessel (4) is associated with a sensing means (16) which ispresettodeterminea high liquid level (17) and a low liquid level (18) inthevessel. The volume ofthe vessel (4) between the high and low levels is the desired volume of carbonated wine for dispensing purposes during a single dispensing operation. Sensing means (16) feeds back information to a control module (19)which is provided with a control connection (20) to outlet valve (14).

Control module (19) also receives information from a temperature sensor (21 ) in cooling bath (9) and can, if desired, automatically switch off refrigeration unit (10) when the temperature of cooling bath (9) measured by sensor (21 ) is below a preset value. Alternatively, or in addition, a control connection (23) can switch off pump (7) or control connection (20) closes valve (14) or inhibits its opening when the temperature of cooling bath (9) measured by sensor (21) is below a preset value. This temperature monitoring function thus can, if desired, inhibit the carbonation and dispense operation entirely if temperature goes below a certain preset value. This is a useful way of preventing over-carbonating of wine.

Gas supply valve (3) includes a vent to atmosphere which provides a pathway for excess gas pressure to leave vessel (4) to the atmosphere if necessary.

The sequencing of carbonating and dispensing operations with respect to the present apparatus for the carbonation of a still wine allowsthe achievement of the maximum level of dissolved carbon dioxide in the wine whilst eliminating the possibility of carbonating above the maximum allowable level. The sequence of events leading to dispensing of a single glass of carbonated wine may be carried out automatically underthe control of module (19) and is initiated by an electrical signal originating from the point of dispense, e.g. the pressing of a button (not shown).

The sequence of operation begins by an examination ofthe actual liquid level in vessel (4) using sensing means (16). If thesis is below high level (17) carbonatorfeed pump (7) is started and continues to run until the level of liquid in vessel (4) reaches high level (17) when the pump is automatically stopped. As the feed pump stops, there is (as described with reference to Figure 2D) automatic activation ofthe solenoid outlet valve (14) by connection (20) putting the valve in the open position and allowing carbonatedwinetoflowtothe dispensing valve (22) and into glass (15). Outlet valve (14) closes again once the liquid level in vessel (4) has returned to low level position (18).This completes the carbonation and dispensing sequence. During this sequence a supply of carbon dioxide (2) is maintained to vessel (4) through control valve (3).

In the event of the above sequence being interrupted for any reason whatsoever the supply of carbon dioxide (2) to vessel (4) is shut off bythe closing of valve (3) and carbon dioxide in vessel (4) may be vented to the atmospherethrough valve (3).

The normal condition at the start of a carbonation dispensing sequence is that residual liquid in vessel (4) is at the low level position (18). This level is predetermined to correspond to a liquid volume in thevessel (4) which is only a very small proportion of the volume that is actually dispensed into a glass.

Naturally, during the period oftime since the previous dispensing of a glass of carbonated wine, the residual liquid in vessel (4) will have absorbed carbon dioxide and will in fact have achieved a higher carbon dioxide content. When carbonator feed pump (7) commences its operation, freshly carbonated wine at a lower carbon dioxide content mixes with this. When the high level (17) in vessel (4) is reached, pump (7) stops as described with reference to Figure 2A. The contents of vessel (4) may be emptied by the means already described into a receiving glass (15). Carbonation conditions, i.e.

temperature and pressure, are such thatthe resulting carbon dioxide content of the dispensed wine does not exceed the maximum legal or desired value. This is adjusted to be the case even allowing for residual liquid in vessel (4) to reach its equilibrium carbon dioxide content.

Of course, the system described allows for automatic volume dispensing of carbonated wine since the outlet valve (14) is opened and closed atthe high and low level positions (17, 18) in vessel (4) as described with reference to Figure 2D. The relative positions of these levels are setto correspond tothe average volume of a wine glass or other desired vessel for receipt of the dispensed wine.

If, for any reason,the volume of wine dispensed from vessel (4) is less than the volume between high level (17) and low level (18),overcarbonation of the resulting largerthan usual residual volume of liquid in vessel (4) is avoided by the termination ofthe supply of carbon dioxide (2) to the vessel and the venting of carbon dioxide in vessel (4) to the atmosphere through valve (3). This will occur automatically if the low level position (18) is not reached within a specified period oftime, and is achieved by the use oftimers, as described with reference to Figure 2C.

In operation of the apparatus, the actual carbon dioxide content of the dispensed carbonated wine may be chosen to allow for maximum control variations in temperature and pressureforthe components ofthe apparatus. Asfurthersafeguards, the temperature monitoring system involving the use of sensor (21) referred to above (preferably as a back up for a standard cooling bath thermostat control, not shown in Figure 1 ) allows the temperatureofcarbonationtobecontrolled and a pressure release may be provided by fitting vessel (4) with a pressure release valve (not shown) set to open if the pressure in the vessel exceeds a predetermined value.

Furthermore, the positioning offlow regulating device (12) upstream of cooling coil (13) ensures, in the manner previously described, that the carbonated wine passing through dispensing valve (14) retains the maximum possible amount of carbon dioxide and minimises loss of carbon dioxide during the dispensing into the glass.

In atypical operation,thefillingtimeforvessel (4) might be three to four seconds and the dispensing time ten seconds. Atypical period of time forthe overall carbonation and dispensing operation would be twenty seconds from the activation of the system.

This is in effect the "residence time" of in contact with the carbon dioxide and is, of course, of importance in determining the carbonation level.

The contact time between gas and liquid in vessel (4) is limited to a maximum value such that over-carbonation cannot occur. This is achieved using a timer (Figure 2D) which causes gas to be automatically vented if a pre-set period oftime is exceeded between initiation of the dispense operation and sensing of the low level (18).

The individual items of equipment used in producing an apparatus as shown in Figure 1 may be conventional itemswell known in the art, e.g. items used extensively in soft drink or still wine dispensing.

Figures 2Ato 2D are schematic diagrams of circuits for controlling the system shown in Figure 1.

These circuits are, in this particular embodiment, based on the use of standard type 555 integrated circuits (as made by, for example, Signetics Corporation), the type 555 circuits having their external pins appropriately connected (in accordance with normal practice) to providethe particular mode of operation required.

Figure 2A is a diagram of the circuit for controlling the motor of the feed pump 7. The circuit has two type 555 circuits 100 and 101. The circuit 100 has a control input 102 which is enabled on operation of the dispense push button to provide a three second delay, adjustable by means of a potentiometer 103.

The second type 555 circuit 101 provides energisation of a relay coil 1 04 which controls two sets 105 and 106 of relay contacts. Each set of contacts has a central movable contact and two fixed contacts. The set 105 of contacts normally provides an opencircuitbetweena line 107to aterminal of a motorforthe pump7 and a power supply line 108, the lines 107 and 108 being connected,to cause energisation of the pump motor, when the relay coil 104 is energised.The contact set 106 operates in correspondencewith the set 105 and is operative to couple either the green light emitting diode 109 (when the pump is operating) or the red light emitting diode 110 (when the relay is de-energised) to the supply line 111. Afurthercontrol input 112 from the sensor which senses the high level of liquid in the carbonator4 controls pin 4Of the pump driver circuit 101. The connection between the pump driver and the relay coil 104 extends through a pair of terminals 113which are rendered open circuit bythe operation ofthe pump protection circuit shown in Figure 2B, which will be described later.

As mentioned earlier, the purpose ofthe pump control circuit isto start the pump when the dispense button is pressed and to stop the pump when the liquid has reached the predetermined level associated with the high level probe in the carbonator4.

When the dispense button is pressed, a logic signal from input 102 is supplied to pin 2 ofthe circuit 100. The timer in this circuit is started and aftera delay of approximately three seconds, which may be adjusted bythe potentiometer 103, a pulsefrom pin3 ofcircuit 100 is routed to pin 2 ofthe pump driver circuit 101, which energises the relay coil 104. The closure ofthe left hand pairofcontacts inthe set 105 energisesthepump motorsothatthepumpstarts and liquid is pumped to the carbonator until the level of liquid in the carbonator reaches the level associated with the high level sensor.Thereupon a signal from that sensor appears on pin 4ofthe pump driver circuit 101, which de-energises relay coil 104 to open the connection between lines 107 and 108 andtherebystopsthe pump. If the signal on pin 4 of the pump driver circuit 101 is already present when the dispense button is pressed, the pump will not start, since the existence ofthis signal indicates that the liquid in the carbonator4 is already at the high level.

Figure 2B is a diagram ofthe pump protection circuit. This includes a 555 type circuit connected as a oneshotwith a thirty second timing period (adjustable by means of a potentiometer 123). The circuit 120 enables a second type 555 circuit 121 which drives a relay coil 124. This relay coil controls two sets of contacts 125 and 126. The contacts 125 provide, on closure of the left hand pair in the set connection of the terminals 113 between the pump driver 101 and the relay ofthe coil 104 in Figure 2A. In the set of contacts 126the right hand pairare normally closed to energise a red light emitting diode 130. This diode is offwhilethe pump is operating and comes on when it stops.

A line 102a enabled on operation ofthe dispense button is connected to pin 2 ofthe circuit 120 and lines 11 2a and 11 2b are coupled to pins 4 ofthe circuits 120 and 121 respectively; these lines 1 12a and 11 2b are enabled when the respective sensor senses liquid at the high level in carbonator4.

The pump protection circuit is provided to inhibit the operation ofthe pump as a safeguard against the emptying ofthewinecontainer6andtherebyto preventthe pump from running dry.

When the dispense button is pressed, the signal on line 102a is applied to pin 2 of circuit 120. Circuit 120 enables the driver 121 to energise relay 124, thereby to close terminals 113. After the adjustable delay (approximately thirty seconds) of the delay circuit 120,thetimertherein will time out to disable driver 121,which will de-energise coil 124 and open circuit terminals 113, thereby preventing further operation ofthe pump. This occurs if a signal from the high level probe has not been received at pin 4 ofthe drivercircuit121. Under normal operation however a signal from the high level sensor is received within approximately ten seconds of the starting ofthe pump and the signal on line 1 12a is applied to pin 4 of circuit 120 in orderto reset the timer therein to zero readyforthe next start signal.

Figure 2C is a diagram of the circuitforcontrolling the gas control valve that controls the flow of carbon dioxide into the carbonator 4. The circuit includes a type 555 circuit constituting a relay driver 131, arrangedwhen enabled to energise relay coil 134 that controls two contact sets 135 and 136. The set 135 has the right hand pairofcontacts normally closed and the left hand pair normally open; on closure of the left hand pair in response to energisation of coil 134 a line 137 to a solenoid for the gas control valve is connected to supply line 138 in order to energise the solenoid and to open the valve. When the valve is closed (to stop the supply of carbon dioxide to the carbonator 4), the valve vents the carbonator 4to atmosphere.The (normally open) left hand pair of contacts of set 136 energise,when closed, a light emitting diode 139 from a supply line 141. Normally,the right hand pair of contacts couple light emitting diode 140 to the supply line 141. Light emitting diode 139 illuminates when carbon dioxide is being supplied through the valve whereas light emitting diode 140 illuminates when the supply of carbon dioxide is cut off.

On the operation of the dispense button, line 102c is energisedto enable pin 2 ofthe relay driver 131, which energises coil 134 and causes opening of the carbon dioxide supply valve. The internal timer of the relay driver is started; the timing period of the timer is adjustable by means of potentiometer 132.

Thevalvewill stay open while the equipment is in operation and does not require resetting each time the dispense button is pressed, unless the timer is circuit 131 times out. The timer is incorporated to ensure that if liquid remains in the carbonatorfor a set time, for example, five minutes, the supply of carbon dioxide is cut off and any remaining carbon dioxide in the carbonator is vented to a predetermined pressure,forexample 1 psi.

The low level sensor controls line 135which is coupled to pins 6 and 7 ofthe relay driver circuit 131.

If a signal from the low level sensor has not been received on those pins to signify that the liquid has been dispensed after the set time (five minutes)the timertimes out and the relay coil 134 is de-energised, to close the supply valve and to ventthe carbon dioxide in carbonator4. The signal on line 133 resets the timer to zero so that the relay driver is not enabled again until the dispense button is pressed.

Figure 2D is a diagram ofthe circuitforcontrolling the outlet valve 14of Figure 1. In the circuit of Figure 2D, a type 555 circuit 142 constitutes a driverfor a relay coil 144 which controls two sets of contacts 145 and 146. The contacts 145 provide normally an open circuit between an electrical supply line 148 and a line 147 to a solenoid controlling the valve 14. The contact sets 146 provide for energisation of eitherthe light emitting diode 149 (when the dispense valve solenoid is energised) orthe light emitting diode 150 (when the dispense solenoid is de-energised). The low level sensor enables line 133a which is connected to pin 4 of the driver circuit 142.

The circuit of Figure 2D is provided to ensurethe outlet valve 14 only opens when liquid has reached a predetermined level in the carbonator 4. While the liquid is atthe low level, the relay coil 144 is de-energised because a signal is present on pin 4 of circuit 142. As the pump7 raises the liquid level in the carbonatorthe high level sensor is activated, to provide a signal on line 1 12c, enabling pin 2 of driver 142 so as to energise coil 144 and thereby to open the outlet valve 14. As liquid is dispensed, the level of liquid in carbonator4falls. When the liquid level reaches the predetermined low level, the line 1 33a controlled by the low level sensor is activated and the driver (constituting in this circuit a bi-stable) de-energises relay coil 144 to close the valve.

Accordingly, the circuit provides, in combination with the sensors for the high level and low level of liquid a meansfordispensing a predetermined volume of liquid.

The particular construction of the sensors is not essential to the present invention but it is convenient to provide a pair of probes, which act as electrodes in the liquid and are ofthe resistive type. For example, an electrode may be common to both the high level probe and the low level probe so that if no liquid is present between the common electrode and the high level or low level probe a high resistance is seen by an associated control circuit; if liquid is present a low resistance is seen by the control circuit. The control circuit (not shown) provides the signals on the various lines 1 12 to 1 12e and lines 1 13 and 1 13a.

Naturally, a control module based upon solid state components and circuit boards is preferred. The control sequence is, of course, ideally designed with amaximum runningtimeforoperationoffeedpump (7) and for outlet valve (14) to be opened.

The manner of operation and control ofthe apparatus of the present invention shown in Figure 3 is largely self-explanatory. It will, however, be noticed that the apparatus ofthe invention desirably incorporates a manual reset facility as an additional precaution againstfaulty operation. Furthermore, the use of preset running times forthe feed pump (7) and the operation of outlet valve (14) provide additional precautionsto prevent over-carbonation.

The design of vessel or carbonator (4) is quite important and the carbonator (27) illustrated in Figure 4 has been designed specificallyfor use with the wine carbonation and dispense system as described above. Carbonator (27) may be made from stainless steel or other suitable material. Wine or other liquid to be carbonated (represented by arrow A) is injected via a spray nozzle (24) into an upper, preferably cylindrical, carbonating chamber (25) where it absorbs carbon dioxide. The resulting carbonated wine collects in the lower, preferably cylindrical, carbonated liquid chamber (26) via aperture (28) from where it is fed to the point of dispense via conduit (11) as described above.The carbonator (27) is also fitted with a connection (2) by which carbon dioxide gas under pressure (represented by arrow B) entersthe carbonator, and a safety valve (29) for the purpose of relieving excess gas pressure from the carbonator. The carbonator (27) is fitted with a level probe (30) or other means for the purpose of controlling the level ofcarbonated liquid in the lower chamber between a lower fixed level (18) and an upperfixed level (17).

The liquid which is required to be carbonated enters the upper chamber under pressure via the spray nozzle (24) in the form of a fine spray. As the sprayed liquid falls through the atmosphere of carbon dioxide in the upper chamber (25) it dissolves carbon dioxide and thereby becomes carbonated.

The carbonated liquid passes into the lower chamber (26) where it accumulates. When the carbonated liquid has accumulated to the point where the level of liquid has reached the upper fixed level (17) as detected bythe level probe (30), the supply of liquid to the carbonator (27) is automatically cut-off.

The carbonator (27) design has the following features which are important to satisfactory operation. First, carbonation takes place in upper chamber (25) and carbonation liquid collects in lower chamber (26). Secondly, as a result of the relatively small diameter ofthe lower chamber (26) in which the carbonated wine collects, the accuracy and repeatability of the dispensed liquid volume is high.

This is because ofthe relationship between the level variation and volume variation. In the lower chamber (26) a iargevariation in liquid level results in a relatively small variation in liquid volume Consequently, the normal inaccuracies which are associated with various available means of liquid level sensing result in very small variations in liquid volume. The equipmentcan bemadetofunction with a dispense volume accuracy and repeatability of betterthan 150 ml i 2 ml. In a conventional carbonator, having a single diameter of say 10cm, the volume changefora 1 mm change in liquid level would be 7.85 ml.The corresponding volume changefora 1 mm change in liquid level in the lower chamber (26) of the present carbonator (27) where the diameterwouldtypically be 3 cm is 0.71 ml. This means thatthe volume of carbonated liquid between the high and low level positions can be more accurately controlled than in a conventional carbonatorfitted with a level sensing device similar to level probe (30). Thirdly, as a result ofthe relatively small surface area of liquid in the lower chamber (26) which is in contact with the gas during its residence in the carbonator (27),the rate at which carbon dioxide continues to be absorbed is extremely slow. This further avoids the risk of wine being carbonated above a maximum desired level.

No known previous carbonator design embodies the above considerations and the invention includes the new design.

Preferably, the diameter of aperture (28) is 1/3 or less of the diameter ofthe diameter of upper chamber (25). Similarly, it is preferred that the diameter of low chamber(26) is 1/3 or less of that of upper chamber (25).

It will be appreciated that the present inventive concept includes as a further aspect a method for dissolving gas in a liquid and repeatedly dispensing afixedvolume ofthe resulting solution comprising supplying the liquid and gas to a vessel so thatthe liquid level in the vessel reaches a first predetermined level but no higher, permitting the gas to dissolve in the liquid, and dispensing the resulting solution from the vessel until the liquid level reaches a second and lower predetermined value but no lower, the volume of the vessel between the first and second predetermined levels being the fixed volume, and the supply of liquid to the vessel and dispensing ofthe resulting solution being operationally linked to the vessel liquid level so that supply of liquid to the vessel occurs when dispensing is initiated if the vessel liquid level is below the first predetermined level and dispensing ceases when the vessel liquid level has decreased to the second predetermined level.

The skilled man will readily appreciate that the present invention may be embodied in many different ways and adapted to suit particular circumstances or modified for special purposes.

Such apparent adaptations and modifications are, of course, included within the scope of the invention.

Claims (5)

1. An apparatus for dissolving a gas in a liquid and repeatedly dispensing a fixed volume of the resulting solution, comprising a vessel for mixing the liquid and gas, meansforsupplying the liquid to the vessel, means for supplying the gas to the vessel, means for determining the liquid level in the vessel, means connected to the liquid level determining means and responsive thereto for activating liquid supply to the vessel if the liquid level is below a first predetermined level so asto raise the liquid level to the first predetermined level but no higher, means for dispensing the resulting solution from the vessel including an outlet valve having open and closed positions, and means connected to the liquid level determining meansforadjustingtheoutletvalveto the open position when the vessel liquid level is at the first predetermined level and for adjusting the outlet valve to the closed position when the vessel liquid level reaches a lower and second predetermined level, the volume ofthe vessel between the first and second predetermined levels being the fixed volume.

2. An apparatus as claimed in claim 1,wherein the outlet valve is solenoid-controlled.

3. An apparatus as claimed in claim 1 or claim 2, wherein the solution dispensing means also includes a manually operated dispensing valve positioned downstream ofthe vessel outlet valve.

4. An apparatus as claimed in claim 3, wherein a conduit is provided for carrying gas/liquid solution to the dispensing valve from the vessel, the conduit being provided with a flow regulating device and downstream of the flow regulating device means for cooling material passing through the conduit before it reaches the dispensing valve.

5. Avessel for dissolving a gas in a liquid substantially as hereinbefore described with reference to and as illustrated in the accompanying drawing.

5. An apparatus as claimed in claim 4, wherein the cooling means comprises a portion ofthe conduit formed as a cooling coil and passing through a refrigerated enclosure.

6. An apparatus as claimed in any one of claims 1 to 5, wherein the meansforsupplying the liquid to the vessel includes means for cooling the liquid.

7. An apparatus as claimed in claim 6when dependentuponclaim 5,whereinthe meansfor cooling the liquid comprises a cooling coil passing through the said refrigerated enclosure.

8. An apparatus as claimed in claim 5 or claim 7, wherein the refrigerated enclosure is thermostatically controlled.

9. An apparatus as claimed in any one of claims 5,7 or 8, wherein the refrigerated enclosure has a temperature sensor positioned therein and is associated with means for preventing operation of the apparatus if the temperature in the enclosure sensed by the sensor drops below a predetermined value.

10. An apparatus as claimed in claim 9, wherein the means for preventing operation of the apparatus includes means for preventing the supply of liquid to the vessel if dispensing of solution has not yet started and for preventing the outlet valve from adopting the open position or for closing the outlet valve if dispensing of solution has started.

11. An apparatus as claimed in claim 10, wherein the meansforsupplying liquid to the vessel includes a pump, the operation ofwhich pump is prevented by operation ofthe means for preventing the supply of liquid to the vessel.

12. An apparatus as claimed in claim 5 or in any one of claims 7 to 11, wherein the refrigerated enclosure has a temperature sensor positioned therein and is associated with meansforswitching off power supply to the refrigerated unit of the refrigerated enclosure ifthe temperature in the enclosure sensed by the sensor drops below a predetermined value.

13. An apparatus as claimed in any one of claims 1 to 12, wherein the means for supplying the gas to the vessel includes meansforventing gas in the vessel to atmosphere.

14. An apparatus as claimed in claim 13 including means for ensuring that if the volume of solution dispensed is less than the volume of vessel between the first and second predetermined levels the supply of gas to the vessel is terminated and gas in the vessel is vented to atmpsphere via said venting means.

15. An apparatus as claimed in any one of claims 1 to 14, wherein the vessel is equipped with the pressure release valve adapted to open if gas pressure therein exceeds a predetermined value.

16. Avessel for dissolving a gas in a liquid comprising an upper chamber provided both with means for supplying the gas thereto and a spray nozzle inletforsupplying the liquid thereto, and a lower chamber opening upwardly into the bottom of the upper chamber through an aperture which is appreciably smallerthan the cross-sectional size of the upper chamber.

17. Avessel as claimed in claim 16, wherein the aperture and the cross-section of the upper chamber are substantially circular, the ratiq ofthe diameter of the aperture to the diameter of the upper chamber being a maximum 1:3.

18. A vessel for dissolving a gas in a liquid comprising an upper chamber provided both with means for supplying the gas thereto and a spray nozzle inlet four supplying the liquid thereto, and a lower chamber opening upwardly into the bottom of the upperchamberand having a cross-sectional size appreciably smallerthan the cross-sectional size of the upper chamber.

19. Avessel as claimed in claim 18, wherein the upper and lower chambers are substantially circular in cross-section, the ratio of upper to lower chamber diameter being a minimum of3:1.

20. Avessel as claimed in anyone of claims 16to 19which isacarbonator.

21. Avessel fordissolving a gas in a liquid substantially as hereinbefore described with reference to and as illustrated in Figure 4 ofthe accompanying drawings.

22. An apparatus as claimed in any one of claims 1 to 15, wherein the vessel is a vessel as claimed in any one of claims 16to 21.

23. An apparatus as claimed in claim 1 and substantially as hereinbefore described.

24. An apparatus for dissolving a gas in a liquid and repeatedly dispensing a fixed volume ofthe resulting solution substantially as hereinbefore described with reference to and as illustrated in Figure 1 or Figure 1 as modified by any one or more of Figures2(a),2(b),2(c),2(d) or4Ofthe accompanying drawings.

25. A method for dissolving a gas in a liquid and repeatedly dispensing a fixed volume of the resulting solution comprising supplying the liquid and gas to a vessel so that the liquid level in the vessel reaches a first predetermined level but no higher, permitting the gas to dissolve in the liquid, and dispensing the resulting solution from the vessel until the liquid level reaches a second and lower predetermined value but no lower, the volume ofthe vessel between the first and second predetermined levels being the fixed volume, and the supply of liquid to the vessel and dispensing of the resulting solution being operationally linked to the vessel liquid level so that supply of liquid to the vessel occurs when dispensing is initiated if the vessel liquid level is belowthefirst predetermined level and dispensing ceases when the vessel liquid level has decreased to the second predetermined level.

26. A method as claimed in claim 25, wherein the gas is carbon dioxide.

27. A method as claimed in claim 25 and substantially as hereinbefore described.

28. A method as claimed in claim 25 and substantially as hereinbefore described with reference to the accompanying drawings, Figure 3 in particular.

29. Acarbonated beverage, eg carbonated wine, which has been produced by the use of an apparatus as claimed in any one of claims 1 to 15 or22to 24ora method as claimed in any one of claims 26 to 28.

Amendments to the claims have been filed, and have the following effect: (a) Claims 1 to 29 above have been deleted or textually amended.

(b) New ortextually amended claims have been filed as follows: CLAIMS

1. A vessel for dissolving a gas in a liquid comprising an upper chamber provided both with means for supplying the gas thereto and a spray nozzle inletforsupplying the liquid thereto, and a lowerchamberopening upwardly into the bottom of the upperchamberthrough an aperture,the aperture being appreciably smaller than the cross-sectional size of the upper chamber and/or the said lower chamber having a cross-sectional size appreciable smaller than the cross-sectional size of the upper chamber (25).

2. A vessel as claimed in claim 1, wherein the aperture and the cross-section of the upper chamber are substantially circular, the ratio of the diameter of the aperture to the diameter of the upper chamber being a maximum 1:3.

3. Avessel as claimed in claim 1 or claim 2, wherein the upper and lower chambers are substantially circular in cross-section, the ratio of upperto lower chamber diameter being a minimum of3:1.

4. Avessel as claimed in any one of claims 1 to 3 which is a carbonator.