EP1699731A2

EP1699731A2 - Method and device for cleaning a beverage conduit in a dispensing system

Info

Publication number: EP1699731A2
Application number: EP04803572A
Authority: EP
Inventors: Rudolf Till
Original assignee: Sparkasse Buehl
Current assignee: Sparkasse Buehl
Priority date: 2003-12-23
Filing date: 2004-12-07
Publication date: 2006-09-13
Also published as: US20070006900A1; WO2005063608A3; WO2005063608A2; DE10361565A1

Abstract

Disclosed are a method and a device for cleaning a beverage conduit (5) in a dispensing system. Said beverage conduit (5) is filled with a cleaning agent. A parameter (UM) representing the cleaning condition of the beverage conduit (5) is measured during cleaning thereof, and the cleaning process is terminated when the parameter (UM) reaches a predetermined setpoint value (US).

Description

Method and device for cleaning a beverage line in a dispenser

The invention relates to a method for cleaning a beverage line in a dispenser, in which the beverage line is filled and cleaned with a cleaning agent.

The invention further relates to a device for cleaning a beverage line in a dispenser, with a cleaning system for filling the beverage line with a cleaning agent. A method and a device of the type mentioned above are known, for example from DE 297 04 794 Ul.

In the known device, a tap head is first knocked off the beer keg in order to clean a beverage line of a beer dispensing system. By opening a valve, water from a water pipe is first enriched with detergent in a detergent dispenser and then pressed into the beverage line leading to the tap. An impeller counter ensures that the entire beverage line is filled with the detergent mixture. After a predetermined service life, the dimensioning of which is a matter of experience, the cleaning agent mixture is drained by opening another valve, and the beverage line is rinsed by repeatedly filling it with water.

Another device of the type mentioned above is known from WO 01/94040. In this known device, a beverage tank is connected to a tap via a beverage line, in which a conductivity meter, a valve unit, a pump and a cooling unit are arranged in the vicinity of the end opposite the beverage tank. The aforementioned units are bridged by means of a circulation line. With the known device, a cleaning program known per se is carried out, in which a cleaning liquid is first poured into the beverage line, which then remains in the beverage line for a certain time and is then drained into a drain by displacement with water. Then the beverage line is filled with water several times and thereby rinsed. Finally, drink is let back into the drink line and with it the drink displaced water. The conductivity meter recognizes which liquid (beverage, cleaning fluid or water) is currently in the beverage line, specifically at the point at which the conductivity meter is located. The conductivity meter controls the transition from one step of the cleaning program to a next step.

The known devices thus have the disadvantage that only the presence of a certain medium at a position of the beverage line is recognized. The extent of cleaning, however, remains dependent on experience. Therefore, there is no guarantee that the entire beverage line has actually been completely cleaned. On the other hand, as is well known, the extent of contamination of a beverage line depends on many factors, e.g. on the consistency of the respective beverage and the ambient temperature of the beverage line in the interval between the cleaning processes, i.e. on factors that cannot be reliably estimated even with experience.

A further disadvantage of the known device is that, at the end of the rinsing process that concludes the cleaning process, it is also not ensured that the beverage line is now free of cleaning agent residues. There is therefore a risk that during the subsequent transition to dispensing operation, detergent residues will get into the dispensed beverage.

The invention is therefore based on the object of developing a method and a device of the type mentioned at the outset such that the disadvantages mentioned are avoided. In particular, it is intended to enable beverage lines in to reliably and reproducibly clean to a predetermined extent and to prevent contamination of the beverage tapped after cleaning with residues of detergent.

This object is achieved according to the invention in a method of the type mentioned at the outset by measuring a parameter reflecting the cleaning state of the beverage line during the cleaning of the beverage line and terminating the cleaning process when the parameter reaches a predetermined desired value.

In the case of a device of the type mentioned at the outset, the object is achieved in that first means are provided in order to measure a parameter reflecting the cleaning state of the beverage line during the cleaning of the beverage line, and second means which end the cleaning process when the parameter reaches a predetermined one Setpoint reached.

The object underlying the invention is thus completely achieved. In contrast to the state of the art, a controlled cleaning including rinsing takes place, in which the current status of the cleaning or rinsing is continuously recorded and the cleaning only ends, for example the cleaning agent is removed or the rinsing is interrupted when the cleaning or the rinsing meets a predetermined criterion.

In one embodiment of the invention, the parameter indicates an electrical conductivity. This measure has the advantage that a parameter was selected here that can be recorded in a simple and reliable manner by measurement technology, in the simplest case namely via a current / voltage measurement.

The electrical conductivity of a medium located in the beverage line and the electrical conductivity of a coating covering an inner surface of the beverage line are preferably determined.

This measure has the advantage that the size that is actually of interest for cleaning, namely the coating in the beverage line, is recorded directly.

Alternatively, the parameter can also indicate a turbidity or a pH value of a medium in the beverage line.

In these variants, the cleaning status is therefore indirect, namely via the medium in the beverage line, e.g. the cleaning liquid is determined. Proven measuring elements and methods can be used. Of course, all of the aforementioned parameter variants can also be combined with one another in order to increase the reliability of the measurement.

A particularly good effect is achieved according to the invention if a value representing a clean beverage line is determined in advance in the beverage line as the desired value. Here too, in contrast to the state of the art, the user does not have to rely on empirical values, but rather can build on objectively determined measured values.

It is further preferred according to the invention if a parameter of a medium in the beverage line is determined as the reference variable for the parameter.

This measure has the advantage that a disturbance variable, namely the influence of the medium in the beverage line, can be eliminated when measuring the parameter.

In this variant, too, the setpoint can be derived from the electrical conductivity, the turbidity or the pH value.

Finally, in a particularly preferred exemplary embodiment of the method according to the invention, the parameter is measured as a first signal upstream and as a second signal downstream of an addition device for the cleaning agent, and a rinsing process which takes place at the end of the cleaning process is only ended when the signals are essentially the same.

This measure has the advantage that at the end of the rinsing process it is ensured that there are no residues of cleaning agent in the beverage line. It is therefore safe to switch back to the tap operation, ie the beverage line can be filled with beverage. In a preferred development of the device according to the invention, the first means contain at least two electrically conductive, but electrically insulated sections of the beverage line, and a first measuring circuit for measuring the electrical conductivity between the sections.

This measure has the advantage that a particularly simple configuration for the first means, i.e. the sensor for measuring the parameter is created, which reflects the cleaning status of the beverage line. The arrangement can be easily integrated into an existing beverage line and is easy to maintain and inexpensive.

Alternatively or in addition, of course, here too, e.g. an opacimeter or a pH meter can be used.

In a preferred embodiment of the device according to the invention, third means are provided for determining a parameter of a medium in the beverage line in the beverage line.

When an electrical conductivity is determined, the third means contain a second measuring circuit and preferably have a further, electrically insulating section in the beverage line, which is preferably arranged between the two electrically conductive sections.

Here, too, the advantages already discussed above result, now also with regard to the third means. Further advantages result from the description and the attached drawing.

It goes without saying that the features mentioned above and those yet to be explained below can be used not only in the combination indicated in each case, but also in other combinations or on their own without departing from the scope of the present invention.

Embodiments of the invention are shown in the drawing and are explained in more detail in the following description. Show it:

Figure 1 is an extremely schematic view of a dispenser, which is equipped with a device according to the invention.

Figure 2 is a schematic representation, partly in section, of an embodiment of a device according to the invention.

3 shows a first electrical equivalent circuit diagram to explain the device according to FIG. 1;

4 shows a second electrical equivalent circuit diagram to explain the device according to FIG. 1; and

Fig. 5 shows a schematic further embodiment of the invention. Figure 1 shows in a highly schematic manner a dispensing system 1, such as is installed in restaurants, for example. The dispenser 1 has a counter 2 which is installed in a dispensing room 3. On the counter 2 there is a tap 4 with which beverages, in particular carbonated beverages, in particular beer, can be tapped. From the tap 4, a beverage line 5 leads down into a basement 6, in which there is a barrel 7 or several such barrels. The beverage line 5 is connected to the barrel 7 by means of a dispensing head 8. Usually in the area of the tap 8, a cleaning system 9 is also connected, which in turn is connected to a water supply network via a water pipe 10.

The cleaning system 9 serves to clean the beverage line 5. After it has been started up, it first ensures that the beverage residue located in the beverage line 5 is pressed back into the barrel 7 or emptied via the tap 4. Then the tap head 8 is knocked off the barrel 7. The cleaning system 9 now introduces a cleaning agent, namely a mixture of a cleaning agent concentrate and water, into the beverage line 5 until it is filled up to the tap 4. The cleaning agent is now left in the beverage line 5 for a certain time and then removed again, for example drained off. Then the beverage line 5 is rinsed several times with water. Then you can tap again, i.e. the beverage line 5 can be filled with the beverage.

Two things are important: First, it must be ensured that the beverage line 5 has been completely cleaned. On the other hand, it must be ensured that the beverage line 5 is completely free of cleaning agents after rinsing.

This is where the invention comes in.

In FIG. 2, 12 as a whole denotes a first exemplary embodiment of a device according to the invention. The device 12 is located in the beverage line 5, as already indicated in FIG. 1 in the area of the counter as an enlarged section.

The beverage line 5 has a first section 5a and a second section 5b. Both sections are electrically conductive and are preferably made of stainless steel. On the inner surface 14 of the pipeline 5, a coating 16 can be seen along its length, which consists of deposits of the respective drink.

In order to clean the beverage line 5, a pump 18 or a pressure vessel or a pressure line is provided in the cleaning system 9.

In a metering device 19, water from the water line 10 is mixed with a cleaning agent concentrate supplied via a line 20, and this mixture is introduced into the beverage line 5 by means of the pump 18 as cleaning agent, as indicated by an arrow 22. The valves and valve controls required for this are also the same for the sake of clarity little shown as the means for draining the detergent after cleaning.

It is important that the inflow of cleaning agent 22 into the beverage line 5 can be controlled, e.g. via the controllable pump shown in FIG. 1. “Controllable” is of course to be understood as meaning all possible forms of metering, that is to say both continuous and clocked metering. The metering can of course also be carried out by corresponding valves in pressurized feed lines Beverage line 5 emptied at the start of the cleaning process and then filled with the cleaning agent, which then remains in the beverage line as long as the cleaning continues.

In the exemplary embodiment shown, a controllable pump 18 is used, as mentioned. This is connected with its control input 23 to the output of a controller 30.

A predetermined setpoint voltage U _{s is} fed to the controller 30 on the input side at a first input 32 and a measured actual value voltage U _{M is} fed to a second input 34. From these two input signals U _s and U _M , the controller forms an actuating signal at its output, which is fed to the pump 18 via an output line 36.

The measured actual value voltage U _M is fed to the second input 34 via an output line 38 from an output terminal 40 of a sensor 42. The sensor 42 contains parts of the electrically conductive sections 5a and 5b of the beverage line 5 and an electrically insulating section 44 located between the sections 5a and 5b. It is important that the two sections 5a and 5b are not otherwise electrically connected to one another.

There is a first measuring point 46a at the upper section 5a in FIG. 1 and a second measuring point 46b at the lower section 5b.

The measuring points 46a and 46b are connected to terminals 48a and 48b. A first current source 50 and a first current meter 52 are connected in series between these measurement points.

In the area of the further section 44 there are a third measuring point 60a and a fourth measuring point 60b, both of which are arranged in the interior of the beverage line 5. These measuring points are led through terminals of the electrically insulating wall of the further section 44 to terminals 62a and 62b. A second current source 64 and a second ammeter 66 are connected in series between these terminals 62a and 62b.

The device 12 operates as follows:

A current is generated with the measuring circuit 46 - 52 described above, which flows from the first measuring point 46a through the conductive wall of the upper section 5a, the covering 16 thereon, through the medium in the beverage line 5, through the covering 16 in the region of the lower section 5b, through the conductive wall and to the second measuring point 46b.

The electrical equivalent circuit diagram for this is shown in FIG. 3. It can be seen from this that if the electrical resistances of the electrical lines and the walls of the electrically conductive sections 5a, 5b are neglected, a series connection of three resistances is measured between the terminals 48a and 48b, namely the resistance R _{G of} the beverage and twice the resistance of the Coverings R _B. If R _{G is} known, the resistance R _B can be determined from a measurement of the current by means of the first ammeter 52. The actual value voltage U _M is then generated in a manner known to the person skilled in the art as a function of the measured resistance R _B , for example proportional to it.

If R _{G is} not known, it is determined in an analogous manner with the measuring circuit 60-66 described above as second, by measuring the current flowing through the medium in the beverage line with the second ammeter 66. The electrical equivalent circuit between terminals 62a and 62b is shown in FIG. 3.

If the beverage line 5 is to be cleaned, the beverage residue still located in the beverage line 5 is first removed. The beverage line 5 is then filled with the cleaning agent 22 by switching on the pump 18.

In a first variant, the cleaning agent 22 remains in the beverage line 5 in a conventional manner, ie the pump 18 is then switched off. In a second variant on the other hand, the cleaning is carried out with the cleaning agent 22 running continuously, ie with the pump running continuously. The same applies if the beverage line is supplied with a valve control from an existing pressure line instead of with a pump 18.

In any case, the value U _M is continuously compared with the previously specified value U _s . When U _{M has reached} the value of U _s , the beverage line 5 is considered clean. The cleaning agent 22 is now pressed out or drained by pumps. A flushing then takes place, which is either carried out in a conventional manner, ie with a number of flushing processes based on empirical values, or likewise under the control of sensor 44 and controller 30.

With the second measuring circuit 60-64, the electrical conductivity of the cleaning agent 22 can be determined if R _{G is} not known. Figure 4 shows the associated equivalent circuit diagram. The value determined in this way can then be used to determine R _B.

To calibrate the first measuring circuit 46-52, the value of U _M can be recorded when the measuring line 5 has been completely cleaned and can be specified as the target value U _s in subsequent cleaning processes.

FIG. 5 shows a further exemplary embodiment of the invention, which serves to ensure that after the rinsing process has ended, the beverage line is free of cleaning agent residues. In the cleaning system 9 there is a first sensor 70 on the input side in the water line 10, behind which the detergent concentrate is metered in and the pump 18 is arranged (not shown). A second sensor 72 is located in an outlet line 71 leading to the beverage line 5 or to the tap head 8. The sensors 70 and 72 are preferably of the same type. For example, they work on the principle of conductivity measurement or turbidity or pH value measurement. The sensors generate signals S- _L and S ₂ , which, for example, reflect the electrical conductivity at the input or output of the cleaning system 9.

The sensors 70 and 72 are connected to a comparator 74, for example a differential amplifier. Its output in turn is connected to a threshold value stage 76, which is controlled below a predeterminable threshold value voltage and preferably detects the input voltage “zero”. The threshold value stage 76 then actuates the switch 78, which ends the cleaning program.

This arrangement works as follows:

As long as the beverage line 5 is cleaned and detergent concentrate is added, the signals S _λ and S ₂ differ. The output of the comparator 74 is then at a finite level and the threshold value stage 76 is not controlled. Only when the beverage line 5 has been successfully rinsed at the outlet of the cleaning system 9 is there no more detergent concentrate, ie when the water from the water line 10 reaches the outlet line 71 unchanged, does S _: = S ₂ and thus the output signal of Comparator 74 to zero, with the result that the threshold value stage 76 is turned on and the switch 78 is actuated. This causes a lot of water to be passed through the beverage line 5, which corresponds to its volume. The rinsing process and thus also the cleaning process are thus completed, whereby it is ensured that no cleaning agent residues are left in the beverage line. It is therefore safe to switch to a tap operation.

It goes without saying that the electronic switching blocks shown in FIGS. 2 and 5 are only to be understood as examples. Their functions can of course also be represented by software.

Claims

claims

Method for cleaning a beverage line (5) in a dispensing system, in which the beverage line (5) is filled and cleaned with a cleaning agent (22), characterized in that during the cleaning of the beverage line (5) the cleaning status of the beverage line (5) reproducing the parameter (U _M; _S, ₂ S) is measured and the cleaning process is terminated when the parameters (UM; S ^ S ₂₎ has a predetermined target value (U _S; S ₁ = S ₂₎ is achieved.

A method according to claim 1, characterized in that the parameter (U _M ; S _lf S ₂ ) indicates an electrical conductivity.

A method according to claim 2, characterized in that the electrical conductivity of a medium located in the beverage line (5) and the electrical conductivity of an inner surface (14) of the beverage line

(5) covering covering (16) is determined.

A method according to claim 1, characterized in that the parameter indicates a turbidity of a medium located in the beverage line (5).

A method according to claim 1, characterized in that the parameter indicates a pH of a medium located in the beverage line (5).

Method according to one or more of claims 1 to 5, characterized in that the setpoint (U _s ) in advance in the beverage line (5) is determined a value reflecting a clean beverage line.

7. The method according to one or more of claims 1 to 6, characterized in that a parameter (R _G ) of a medium located in the beverage line (5) is determined as the reference variable for the parameter.

8. The method according to claim 7, characterized in that the parameter indicates an electrical conductivity.

9. The method according to claim 7, characterized in that the parameter indicates a turbidity.

10. The method according to claim 7, characterized in that the parameter indicates a pH.

11. The method according to one or more of claims 1 to 10, characterized in that the parameter as the first signal (S) upstream and as the second signal (S ₂ ) downstream of an addition device (19) for the cleaning agent (22) measured and a The rinsing process taking place at the end of the cleaning process is only ended when the signals (SI, S2) are essentially the same.

12. Device for cleaning a beverage line (5) in a tap system, with a cleaning system (9) for filling the beverage line (5) with a cleaning agent (22), characterized in that first means (42; 70, 72) are provided, to check the cleaning status of the beverage line during the cleaning of the beverage line (5) line (5) reproducing parameters (U _M ; S _1A S ₂ ), and second means (30) that end the cleaning process when the parameter (U _M ; S _< S ₂ ) a predetermined target value (U _s ; S _X = S ₂ ) reached.

13. The apparatus according to claim 12, characterized in that the first means (42) contain at least two electrically conductive, but electrically insulated sections (5a, 5b) of the beverage line (5), and a first measuring circuit (48 - 52) for measuring the electrical conductivity between the two sections (5a, 5b).

14. The apparatus according to claim 12, characterized in that the second means contain a turbidity meter in the beverage line (5).

15. The apparatus according to claim 12, characterized in that the second means contain a pH meter in the beverage line (5).

16. The device according to one or more of claims 12 to 15, characterized in that third means (60-66) are provided to determine in the beverage line (5) a parameter of a medium located in the beverage line (5).

17. The apparatus according to claim 16, characterized in that the third means (60-68) contain a measuring circuit (62-66) for measuring the electrical conductivity of a medium in the beverage line (5).

18. The apparatus according to claim 16, characterized in that the third means contain a turbidity meter for measuring the turbidity of a medium located in the beverage line (5).

19. The apparatus according to claim 16, characterized in that the third means contain a pH meter for measuring the pH of a medium located in the beverage line (5).

20. The device according to one or more of claims 16 to 19, characterized in that the third means are arranged in an electrically insulating further section (44) of the beverage line (5).

21. The apparatus according to claim 5 and 20, characterized in that the further section (44) between the two electrically conductive sections (5a, 5b) is arranged.

22. The device according to one or more of claims 12 to 21, characterized in that sensors 70, 72 for detecting the parameter as a first signal (S ₁ ) upstream and as a second signal (S ₂ ) downstream of an addition device (19) for the cleaning agent (22) are provided, and that the sensors cooperate with fourth means (74-78) which only end a rinsing process that takes place at the end of the cleaning process when the signals (SI, S2) are essentially the same.