WO2009047000A1

WO2009047000A1 - Electronic dosing device for additives in beer dispensing systems

Info

Publication number: WO2009047000A1
Application number: PCT/EP2008/008592
Authority: WO
Inventors: Florian Koch; Georg Fischer
Original assignee: Carbotek Holding Gmbh
Priority date: 2007-10-10
Filing date: 2008-10-10
Publication date: 2009-04-16
Also published as: DE102007048570A1; DE102007048570B4

Abstract

A dosing device for installation in a beer dispensing system and for dosing at least one additive used in the preparation of a beverage. The dosing device has a flow meter that is designed to provide an electrical flow signal that corresponds to the flow of a preliminary beverage product. The dosing device further comprises a valve with a control input for an electrical valve control signal that influences the position of the valve, and also a control device that is electrically linked via respective connections with the flow meter and the valve. The control device is designed to receive the flow signal and to provide the valve control signal, so that the dosing of the additive is proportional to the flow of the preliminary beverage product.

Description

Title: Electronic dosing device for additives in beer dispensing systems

The invention relates to a dosing device for additives, which can be used in a beer dispensing system. The invention also relates to a beer dispensing system with inline gasification and a dosing device of the aforementioned kind.

In drink dispensing systems, a beverage is supplied from a beverage container via a bever- age supply line to a dispensing tap located usually at a higher level. In customary drink dispensing systems the beverage supply line is a dispensing line, while in dispensing systems that incorporate inline gasification, or pressurized gasification stages on the dispensing side, one or more impregnators can also be arranged in the beverage supply line, and by means thereof a preliminary beverage product can be enriched, for example with carbon dioxide, as an additive. A corresponding process is described in German patent DE 10 2005 062 157. In so-called post-mix dispensing systems, the beverage supply line may also in addition contain mixing valves for syrup with an inline gasified water, and a buffer container in which the water is gasified under a carbon dioxide atmosphere.

In dispensing systems that produce the ready-to-drink beverage from a preliminary beverage product and from one or more additives while the beverage is actually being dispensed, it is important that the above-described mixing ratios between the preliminary beverage product and the additive are maintained as accurately as possible. If the mixing ratio is not kept within narrow tolerances, fluctuations in flavour and quality occur and these may negatively affect the enjoyment of the beverage.

The actual mixing ratio at a particular point in time is determined by the volume flows of the substances to be mixed that are attained in a mixing zone. The volume flows are in turn determined by the pressure conditions in the dispensing system, and these may vary with time. In conventional dispensing systems a supply pressure is provided, for example, by means of a compressed gas (e.g. carbon dioxide), the pressure of which is applied to a beverage keg or container so that the beverage is forced upwards via the dispensing line to the dispensing tap. In another type of dispensing system, no pressure is applied to the prelimi- nary beverage product, but instead is extracted by means of a pump from a container and pumped into the dispensing system. In both cases the supply pressure may fluctuate.

The volume flow per time unit that is attained in the mixing zone depends substantially on the speed with which the person operating the tap dispenses the beverage. If the dispensing speed changes, the pressure gradient from the additive supply side or the liquid supply side to the mixing cell also changes, so that the degree of opening of the additive supply and of the liquid supply fluctuate, although the pressure is set at a fixed value. As a result, the volume flows in the mixing zone also vary, so that the additive-liquid mixing ratio may deviate from the optimum.

The German patent application DE 10 2006 048 456 shows a mixing zone inlet device with a liquid inlet valve and a gas inlet valve. The liquid inlet valve and the gas inlet valve are coupled together in such a way that the gas inlet valve sets the gas inlet at a predetermined degree of opening, depending on the degree of opening that is attained by the liquid inlet. The degree of opening of the liquid inlet is determined by the pressure acting on it, so that a high pressure brings about a large degree of opening. This device assumes the role of a dosing device for an additive, in particular a gas.

The arrangement described in patent application DE 10 2006 048 456 is able to keep the mixture ratio constant in a satisfactory way. Because of the pressure-controlled opening of the liquid inlet, pressure fluctuations act more strongly on the volume flow so that an oscillating liquid flow can occur at the dispensing tap, particularly in connection with pumping, and this makes comfortable dispensing difficult. In addition, in terms of fluid dynamics the liquid inlet is a critical point at which turbulent flows and swirling can occur, which can be undesirable upstream of the mixing zone, increasing the flow resistance of the entire dispensing system. Finally, the desired coupling of the liquid and gas inlets requires a high degree of precision in the manufacture of the device.

It is the task of the invention to provide a dosing device that achieves a good mixing result with a high degree of reliability and without the aforementioned disadvantages. According to the invention, a dosing device for mounting in a beer dispensing system and for dosing at least one additive used in the preparation of beverages is provided. For this purpose, the dosing device comprises a flow meter designed to provide an electrical flow signal that corresponds to a flow of a preliminary beverage product, a valve having a con- trol input for a valve control signal influencing the position of the valve, and a control device that is electrically linked with the flow meter and the valve via respective connections. The control device is designed to receive the flow measuring signal and to provide the valve control signal, so that the dosing of the additive is proportional to the flow of the preliminary beverage product.

Electrical flow meters, i.e. devices for measuring a liquid or gas flow, which provide the measuring signal at an electrical interface, are nowadays cheaply available in a wide range of variants. The same goes for valves for blocking, releasing and/or regulating a flow of liquid or gas, numerous variants of which also exist with an electrical interface.

The electrical flow signal corresponds to the flow of the preliminary beverage product. The electrical flow signal can, for example, be proportionally dependent on the flow of the preliminary beverage product. Alternatively, the electrical flow signal may be a binary signal that indicates whether the flow of the preliminary beverage product exceeds or falls below a certain threshold value.

The valve control signal can be a clocked binary signal that causes the valve to assume a fully closed position when the valve control signal attains a first value, and a fully open position when the valve control signal attains a second value. A binary signal is usually capable of assuming or presenting two values. Alternatively, the valve could be designed as a binary valve (open / closed) and the valve control signal could be a signal that can assume any desired value. In this case, the valve compares the valve control signal with a threshold value and correspondingly assumes the closed or open position. Because the valve control signal is clocked, any desired degree of valve opening, averaged over time, can be achieved with just two valve positions by varying the time for which the valve remains in the closed or open position. A mean degree of valve opening can thus be achieved by appropriately selecting the duty cycle. The control device can be designed to vary the duration and/or the frequency of the pulses of the clocked valve control signal. The duration and/or the frequency of the pulses of the clocked valve control signal are parameters that have an effect on the duty cycle and thus on the degree of valve opening, averaged over time. With regard to the frequency of the valve control signal, it should be noted that the valve usually has a maximum operating frequency that should not be exceeded, in order to avoid uncontrolled operation and excessively rapid wear. The dependency relationship between the duration/frequency of the valve control signal and the flow signal can be achieved by various means, for example by analogue electrical components (resistors, capacitors, non-linear components, etc.), by ta- bles or characteristic diagrams stored in a memory, or by performing calculations using one or more formulae.

The control device may be a time switch by means of which, for example, the duration and the frequency of the pulses of the valve control signal can be controlled.

The valve may be a control valve, a flow regulator or a clocked open/shut valve. A control valve permits the degree of opening of the valve to be continuously varied. On the other hand, a flow regulator ensures that a predetermined flow rate (in this case of the additive) is maintained as accurately as possible. In turn, a clocked open/closed valve sprays many small units of volume of the additive into the mixing zone. By counting the number of volume units it is possible to determine and thus control the volume flow of the additive. A valve, which can be a control valve, a flow regulator, a clocked valve or a similar component, permits the volume flow of the additive to be precisely adjusted.

The flow meter can be a dosing pump, an impeller-type meter, a turbine-type meter, a magneto-inductive flow meter, or any other suitable measuring device.

The dosing device can in addition comprise a pressure sensor that is electrically connected to the control device. The pressure sensor is used to measure a pressure in the preliminary beverage product, a pressure in the additive, and/or a differential pressure between the preliminary beverage product and the additive. The pressure values determined in this way can be used to determine the flow rate and/or to determine the optimal degree of valve opening.

The control unit can be designed to determine the dosing of the additive and the valve con- trol signal required for this, on the basis not only of the flow signal but also of the measurement supplied by at least one pressure sensor. If there is a large difference in pressure between a reservoir for the additive and the mixing zone, i.e. a significantly higher pressure exists in the additive reservoir compared with the mixing zone, the valve must be opened only slightly in order to permit a certain amount of additive to reach the mixing zone. If, on the other hand, the difference in pressure is low, i.e. the pressure in the additive reservoir is only slightly higher than the pressure in the mixing zone, the valve must be opened further in order to allow the same amount of additive to reach the mixing zone.

A beer dispensing system may comprise at least one dosing device of the kind described above. If the beer dispensing system comprises several dosing devices in order, for example, to add several different additives to the preliminary beverage product, consideration may be given to providing only one flow meter in order to reduce the number of components. Also, only one control device is needed, in which case however it provides different electrical interfaces for the various valves for the various additives, in order to permit indi- vidual dosages of the additives to be applied.

It is also conceivable to integrate components of the dosing device into already existing components of an inline gasifying-type dispenser system. For example, the mixing chamber and the valve for the additive can be designed as a single component. If necessary, the impregnator can also be incorporated.

The individual features of the embodiments according to the claims can be combined as desired, to the extent that it appears sensible to do so. It goes without saying that the features mentioned above and those still to be explained below, may be used not only in the combinations described, but also in other combinations, or alone, without going outside the bounds of the invention. Individual advantageous embodiments of the invention are described in detail below, with reference to the accompanying drawings, which show:

Figure 1 a block circuit diagram of a beer dispensing system with a first embodiment of the dosing device according to the invention.

Figure 2 a block circuit diagram of a beer dispensing system with a second embodiment of the dosing device according to the invention.

Figure 3 a block circuit diagram of a beer dispensing system with a third embodi- ment of the dosing device according to the invention.

Figure 4 the time courses of two signals that occur in the dosing device shown in

Figure 3.

Figure 5 a block circuit diagram of a beer dispensing system with a fourth embodiment of the dosing device according to the invention.

To start with, reference is made to Figure 1 in order to explain the basic functioning of a beverage dispensing system, in particular a beer dispensing system with inline gasification.

A container 10 is filled with a preliminary beverage product 11. In the example shown of a beer dispensing system with inline gasification, this preliminary beverage product is a low- CO₂, in particular a CO₂-free intermediate beer product. The preliminary beverage product is supplied preferably in non-pressurized or barely pressurizable containers. A barely pres- surizable container is one that withstands up to 0.5 bar gauge pressure. However, this requirement can be met with little expenditure of effort, so that the containers for the preliminary beverage product are cheap.

A pump 12 is used to draw the preliminary beverage product 11 from the container 10 and to pump it into the piping system of the actual beverage or beer dispensing system. The pump may be powered electrically or by compressed air. It may be a geared pump, a centrifugal pump, a vane pump, a peristaltic pump or another type of pump. The pump 12 is switched on when a dispensing process is commenced, i.e. when a person operating the dispensing system opens the dispensing lever. Opening the tap allows the liquid to be dispensed to flow out and the pressure in the pipe system drops. As a rule, the pump has an integrated pressure sensor that registers this and ensures that the pump switches on again.

When the pump 12 is operating, the preliminary beverage product flows through the piping of the dispensing system on the output side of the pump. A flow meter 13 is capable of detecting such a flow. Detection of the flow can provide a numerical value of the actual flow or a binary signal (pulse). The electrical signal is transmitted (dashed line) from the flow meter 13 to a control device 14 via suitable transmitting means.

Impeller-type flow rate meters transmit electrical signals. For example, 1 litre = 1100 signal pulses. One pulse thus corresponds to 1/1100 = 0.91 mL.

The preliminary beverage product passes into a mixing chamber 16 after it has gone through the flow meter. The purpose of the mixing chamber 16 is to mix the preliminary beverage product with an additive. In the present case, carbon dioxide (CO₂) is the additive that turns the intermediate beer product into a beer that is ready to be consumed. The additive can, however, also be a syrup in order to add a flavour to the beverage. But it may also be the case that the preliminary beverage product is a beer syrup and the additives are water and CO₂ and possibly flavouring agents.

The additive comes from a reservoir, such as a CO₂ gas bottle or cartridge (not shown). The amount of additive flowing into the mixing chamber 16 is regulated by a valve 15, which is shown as a control valve in Figure 1. A control valve can assume not only an open and a closed position, but also a large number of intermediate positions, or even as many intermediate positions as desired. The valve 15 has an electrical interface that is connected to the control device 14 (dashed line). A valve control signal is transmitted to the valve 15 via the electrical connection from the control device 14 to the valve. Depending on the valve control signal, the valve 15 allows more or less additive (CO₂) to pass through to the mixing chamber 16. But the CO₂ pressure must then be precisely defined. By vary- ing the pressure, the CO₂ volume flow can in fact be changed. The CO₂ concentration can thus be regulated both via the pressure, as well as via the control device.

It is customary to arrange a check valve 15a between the control valve 15 and the mixing chamber 16, so that no liquid can get into the control valve 15.

The mixture made up of the preliminary beverage product and the additive passes from the mixing chamber 16 into an impregnator 17. The impregnator 17 ensures that the additive is dissolved as completely as possible in the preliminary beverage product. A through-flow cooler may be positioned between the mixing chamber 16 and the impregnator 17.

Finally, the ready-to-drink beverage 18 emerges from the impregnator 17. Depending on how high the pressure that is required to operate the impregnator, the pressure of the beverage is reduced downstream of the impregnator and upstream of the dispensing tap in or- der to achieve a customary pressure of 1.0 to 2.5 bar at the tap. For this purpose the pipe may be spiral-shaped or a pressure compensator can be used, or the pipe cross section is reduced so that the resistance is increased. If a compensator dispensing tap is used, the pressure can also be reduced directly in the dispensing tap.

Figure 2 shows a second embodiment of the invention that corresponds to the embodiment shown in Figure 1 , but has several components added. In particular, two pressure gauges have been added to the dosing device shown in Figure 1. A first pressure gauge 23 measures the pressure of the preliminary beverage product before it enters the mixing chamber 16. A second pressure gauge 25 measures the pressure of the additive upstream of valve 15. From the values that are supplied by the flow meter 13, the pressure gauge for the preliminary beverage product 23 and the pressure gauge for the additive 25, the control device 14, to which these values are electrically transmitted, can determine a control variable for the valve 15. When the pressure conditions in the system are known, it is possible to better estimate how the preliminary beverage product and the additive relate quantitatively to each other and what influence the position of valve 15 has on this relationship. The pressure gauge 23 can also be directly integrated in the mixing chamber 16. Figure 3 shows another embodiment of the dosing device according to the invention. In this embodiment, the flow meter is a pressure switch 33 that opens or closes an electrical contact once a certain pressure is reached. The threshold value for the pressure is usually adjustable. The pressure switch 33 puts out an sPS (signal pressure switch) signal for as long as the pressure on the line between the pump 12 and the mixing chamber 16 exceeds a certain threshold value. In many types of pumps, periodical pressure fluctuations occur because of the operating cycles of the pump. For example, pressure membrane pumps produce pressure pulses during operation. A pressure pulse corresponds to one stroke of the pump and thus to an exactly defined volume of liquid, e.g. 9 mL in the case of the Flojet G56 pump. One pulse thus corresponds exactly to this amount. The resulting course of the pressure values is shown in the upper time graph in Figure 4. The threshold value of the pressure switch 33 is indicated by the dashed line. The pressure switch 33 closes each time the pressure exceeds the threshold value, as is shown in the middle graph in Figure 4. The dosing device also comprises a pulse generator 34. This is designed to generate pulses of a certain duration and, if necessary, at a certain frequency, and to transmit them as a pulse generator signal sT (see Figure 4, lower time graph) to a stop valve 35. Depending on the pulses in the pulse generator signal, the stop valve 35 is opened or closed. In the example shown, a pressure pulse corresponds to a control pulse for the stop valve 35. However, other relationships between the number of pressure pulses and the control pulses for the stop valve 35 are conceivable. The duration of the control pulses of the signal sT is largely independent of the duration of the pulses of the sPS signal and can be adjusted according to the required dosing. Some parameters of the pulse generator signal sT are shown in Figure 4: The spacing T between two pulses (i.e. the reciprocal of the pulse frequency) and the pulse width W. The ratio W/T is referred to as the duty cycle and indicates how long the stop valve 35 is proportionately opened. By appropriately selecting the duty cycle, it is thus possible, averaged over time, to adjust how much additive enters the mixing chamber. Compared with control valves, stop valves are simpler and cheaper. With the embodiment according to Figures 3 and 4, the ability of a control valve to achieve any desired mixing ratios of preliminary beverage products and additive can also be achieved with a simple stop valve - at least averaged over time. Suitable available stop valves support a switching frequency of 1 to 3 Hz. Since the pulses are relatively short and follow each other in rapid succession, there are no serious concentration peaks of the additive in the preliminary bev- erage product. If necessary, the additive concentration can be equalized over time by design measures within the mixing chamber or the impregnator, e.g. by providing a compensation volume in the additive line between the valve 35 and the mixing chamber 16, or a longer remain time in the impregnator.

The dosing device from Figure 3 can be upgraded by adding the pressure gauges 23, 25 from the embodiment shown in Figure 2. Also, the pressure switch 33 can be replaced by a flow meter 13, e.g. an impeller-type sensor, a turbine-type sensor or a magneto-inductive sensor, that provides a relatively accurate measurement for the flow rate. If the flow meter puts out a pulsed electrical signal, e.g. a pulse for every 9 mL, a pulse counter can be provided between the flow meter and the pulse generator 34 to count the number of measured pulses and thus determine the amount of fluid that has flowed through. As soon as a certain amount of preliminary beverage product has flowed through, the pulse counter gives a signal to the pulse generator. In turn, the pulse generator gives a signal to the stop valve 35 in the form of one or more pulses of a defined duration. This principle can also be used if a pump that produces high-frequency pressure fluctuations when in operation and a pressure switch that reacts to the pressure fluctuations are used. It may be that the frequency of the pressure fluctuations is above the permitted operating frequency of the stop valve. Thus, a cycle of the stop valve corresponds to a plurality of pressure pulse cycles.

If there are several additives to be dosed, a corresponding number of valves must be provided. However, the number of devices for measuring pressure and flow rate does not necessarily have to be increased because their measurements can be used for several dosing valves. One exception in this case are the pressure sensors for the pressure of the respective additive in its reservoir. If there are several additive valves, the control device has a corresponding number of electrical interfaces at which the valve control signals for the various valves are present. Figure 5 shows a corresponding arrangement with a control valve for CO₂ dosing and a stop valve 56 for dosing a syrup SIR. The pressure of the syrup SIR upstream of the stop valve 56 is detected by a pressure sensor 55, which allows the difference in pressure with regard to the preliminary beverage product to be determined. -l ilt goes without saying that deviations are possible from the embodiments shown, without going beyond the bounds of the invention. In addition, the features of the embodiments shown can be combined in any desired way.

List of reference numbers:

10 Container for preliminary beverage product

11 Preliminary beverage product 12 Pump

13 Flow meter

14 Control device

15 Proportional valve

16 Mixing chamber 17 Impregnator

18 Beverage ready to be dispensed

23 Pressure gauge for preliminary beverage product

25 Pressure gauge for additive

33 Pressure switch 34 Pulse generator

35 Solenoid valve

Sps Output signal of the pressure switch

S_T Output signal of the pulse generator

Claims

1. A dosing device for installation in a beer dispensing system and for dosing at least one additive used in the preparation of a beverage, having a flow meter that is designed to provide an electrical flow signal that corresponds to the flow of a preliminary beverage product, having also a valve with a control input for an electrical valve control signal that influences the position of the valve, and also a control de- vice that is electrically linked via respective connections with the flow meter and the valve, the control device being designed to receive the flow signal and provide the valve control signal, so that the dosing of the additive is substantially proportional to the flow of the preliminary beverage product.

2. A dosing device according to Claim 1, in which the valve control signal is a clocked binary signal that causes the valve to adopt a fully closed position when the valve control signal attains a first value, and a fully open position when the valve control signal attains a second value.

3. A dosing device according to Claim 2, in which the control device is designed to vary the duration and/or the frequency of pulses of the clocked valve control signal as a function of the flow signal.

4. A dosing device according to Claims 2 or 3, in which the control device comprises a time switch.

5. A dosing device according to Claim 4, in which the control device comprises a pulse counter designed to count measurement pulses coming from the flow meter.

6. A dosing device according to Claim 1, in which the valve is a control valve, a flow regulator or a clocked open/closed valve.

7. A dosing device according to any of the preceding claims, in which the flow meter is an impeller-type meter, a turbine-type meter or a magneto-inductive flow meter.

8. A dosing device according to any of the preceding claims, comprising in addition at least one pressure sensor electrically connected with the control device to measure a pressure of the preliminary beverage product, a pressure of the additive and/or a pressure difference between the preliminary beverage product and the additive.

9. A dosing device according to Claim 6, in which the control unit is designed to de- termine the dosing of the additive and the valve control signal required therefore, on the basis of the flow signal and of the measurements provided by at least one pressure sensor.

10. A beer dispensing system with in-line gasification comprising at least one dosing device according to any of the preceding claims.