Method and apparatus for preserving beverages with pump venting - Patents.com

Abstract

The invention relates to a device (1) for preserving a beverage, characterized in that it comprises a measuring device (3) suitable and intended for determining the flow rate of a liquid flowing through a beverage line (10), a pumping device (4) for conveying a preservative, in particular a dialkyl dicarbonate, into the beverage line (10), the pumping device (4) being controllable as a function of the flow rate determined by the measuring device (3), and a venting device (2) for venting the pumping device (4), the venting device (2) comprising a valve device (22).

Description

[Technical field]

[0001] The present invention relates to a method and device for preserving beverages, and to the use of the device for this purpose. [Background technology]

[0002] Preservatives such as dialkyl dicarbonates, sulfur dioxide, natamycin, benzoates or sorbates are used in the beverage industry for pasteurization of non-alcoholic sparkling or non-sparkling fruit juice drinks, fruit juices, wines, non-alcoholic wines, ciders, iced teas and other beverages. Dialkyl dicarbonates, especially dimethyl dicarbonate or diethyl dicarbonate, represent special pasteurizing agents with several advantages. A notable advantage lies in the fact that, in contrast to hot filling, the taste and color are not affected. Also, compared to persistent preservatives such as sodium benzoate or benzoic acid or potassium sorbate or sorbic acid, the advantage is, among other things, that the taste is not impaired and the effect disappears. Dialkyl dicarbonates decompose into harmless components, so that the actual consumer does not ingest the preservative.

[0003] The advantage of using dialkyl dicarbonates compared to low-temperature aseptic filling is the significantly lower investment costs in plant technology.

[0004] According to the state of the art, only on-line diaphragm dosing pumps are used for the addition of dialkyl dicarbonate. This is necessary because the amount of beverage to be treated is not fixed from the start. The advantage of a diaphragm pump is that the pump chamber is completely sealed.

[0005] A diaphragm pumping system typically consists of a magnetically or electrically driven diaphragm pump, a storage vessel, a device attached to the beverage line for atomizing the dialkyl dicarbonate, a flow meter attached to the beverage line, and an electronic control system. This type of dosing pump is typically permanently installed in the beverage line.

[0006] Dosing pumps must be suitable for several different performance parameters, especially for small and very small volumes. In addition, they must have high dosing accuracy, high atomization pressure, and a wide control range.

[0007] The mode of operation of these devices is based on the online measurement of the flow rate of the beverage through the beverage line and the parallel calculation of the amount of dialkyl dicarbonate to be dosed. The dialkyl dicarbonate is thus dosed proportionally in the required amount into the beverage line. An example of these pumps is the VelcorinDT unit from the company Lanxess.

[0008] In the processing of beverages, such as non-alcoholic soft drinks or wine or mixed beer beverages, a low-temperature sterilization treatment with dialkyl dicarbonate may be necessary, for example to combat bacteria or yeasts, and therefore the above-mentioned dosing device is used for the processing.

[0009] A dosing pump for metered delivery of liquids is known from WO1998042983. Summary of the Invention

[0010] The dosing pumps used in such devices and methods must meet various performance parameters: on the one hand, they must be suitable for the delivery of small or very small quantities, in addition, they should have high precision and at the same time provide high atomization pressures and have a wide control range, especially for the most diverse applications.

[0011] However, it has been shown that the preservatives used cause a certain degree of degassing, and the pumps used in the state of the art are sensitive to the degassing medium, which can lead to large fluctuations in dosage and even malfunction.

[0012] Based on the prior art, the objective is therefore to stabilize the dosing process. This is achieved according to the invention by the subject matter of the independent patent claims. Advantageous embodiments and further developments are the subject matter of the dependent claims.

[0013] The device for preserving a beverage according to the invention comprises a measuring device suitable and intended for determining the flow rate of a liquid flowing through a beverage line, and a pumping device for conveying a preservative, in particular a dialkyl dicarbonate, to the beverage line, the pumping device being controllable as a function of the flow rate determined by the measuring device.

[0014] According to the invention, the device for storing a beverage comprises a vent or degassing device for venting a pump device, the vent device comprising a valve device.

[0015] The invention described herein in particular helps to take precautions to achieve a dosing process that is as gas-free as possible, and in particular helps to safely remove air bubbles from the pumping device.

[0016] Preferably the device has a delivery line which opens into the beverage line and preferably the pump device delivers the preservative through the delivery line.

[0017] In the following, for simplicity, the term "vent" is used even if the vented medium is a gas other than air. Preferably, the gas is a gas selected from the group of gases containing CO2, methanol, methyl carbonate, and dimethyl carbonate.

[0018] In a further preferred embodiment, the device has a nozzle arrangement, in particular a nozzle head for injecting the preservative into the beverage line and / or for atomizing the preservative in the beverage line and / or in the beverage, which nozzle arrangement or this nozzle head preferably protrudes at least partially into the beverage line.

[0019] Preferably, the nozzle device or nozzle head is a component of a delivery line, in particular forming the end of said delivery line.

[0020] Thus, preferably, the pump device serves to inject the preservative into the beverage line and / or into the beverage. Preferably, the pump device is a pump device suitable and intended for the conveyance under pressure of a medium, in this case a preservative, and / or a pump device suitable and intended for producing an atomization of the preservative in the beverage line.

[0021] Preferably, the valve device is a controlled valve device, by which is understood a (particularly active) valve device that can be actively actuated by a control process and that does not open due to overpressure or flow movement, such as in particular a check valve.

[0022] The present invention therefore describes an apparatus and method for venting a pump, in particular for venting a pump head, and especially for fully automatic venting of the pump head, in which, in addition, the option of manual and / or user intervention is preferably also provided, as will be described in detail below.

[0023] In a particularly preferred embodiment, the pumping device is a dosing pump, in particular a diaphragm pump or a diaphragm dosing pump. Diaphragm pumps have proven to be suitable pumping devices for meeting the abovementioned criteria.

[0024] In a preferred embodiment, the pumping device has a flow rate of more than 0.01 l / h, preferably more than 0.02 l / h. Preferably, the pumping device has a flow rate of less than 60 l / h, preferably less than 50 l / h, preferably less than 40 l / h, preferably less than 30 l / h, preferably a maximum of less than 20 l / h.

[0025] Preferably, the pumping device can be controlled within a power range in which the ratio between the minimum flow rate and the maximum flow rate is less than 0.1, preferably less than 0.01. In this way, a wide variety of beverage filling requirements can be met with a single type of pump.

[0026] Preferably the pump device delivers the preservative to the nozzle device under pressure, preferably between 5 bar and 100 bar, preferably between 15 bar and 50 bar.

[0027] Preferably, the beverage is conveyed through the beverage line at a flow rate between 40 l / h and 80000 l / h.

[0028] Particularly preferably, the above-mentioned valve device serves to vent the pump head of the pump device and / or a predetermined area of ​​the pump device in which the degassed medium may collect and / or which pushes the medium to be injected in the direction of the beverage line.

[0029] The pump head is sometimes called the dosing head or the delivery unit in the literature. In particular, the pump head is the area through which the medium to be conveyed flows (is sucked in and / or conveyed). Preferably, the pump head is bounded by the suction valve, the pressure valve and the delivery element (such as the membrane of the piston). The pump head can therefore also be called the "dosing device".

[0030] In a further preferred embodiment, the valve device is a solenoid valve. Solenoid valves or solenoid-controlled valves have the advantage that they can be switched very quickly and also at very high cycle rates.

[0031] In a further advantageous embodiment, the device for storing a beverage comprises a control device for controlling the valve device, in particular the valve device designed as a solenoid valve, which control device is particularly suitable for cyclical control of the solenoid valve.

[0032] Particularly preferably, the control device is suitable and intended for controlling a valve device which responds to or takes into account the (delivery) movement of the pump device, in particular the pump stroke, e.g., a solenoid valve can be controlled periodically every n pump stroke, n being preferably a natural number.

[0033] For example, the valve device can be controlled taking into account the position of an element of the pump device, for example the position of the pump piston, the diaphragm of a diaphragm pump or the position of a valve of the pump device (particularly if the pump device is a diaphragm pump). Preferably, a detection device is provided which detects this position. However, it is also possible to obtain this data from the pump control.

[0034] Furthermore, as will be explained in detail below, the control device is also suitable and intended to control the valve device according to the different operating modes of the device. For example, in the injection mode, it is possible to open the valve device periodically in order to safely evacuate air bubbles that arise in this injection mode. A more detailed procedure is given below. This periodic opening of the valve device is preferably adapted to the pump cycle of the pump device.

[0035] In a further preferred embodiment, the device for preserving a beverage comprises a monitoring device for monitoring the venting process. In this way, even during operation, it can be constantly monitored whether and to what extent venting is taking place or is necessary. The control of the valve can be adapted to this monitoring.

[0036] In a preferred embodiment, the valve device can also be actuated manually and / or by user intervention. For example, manual operation of the valve device is also possible. In this way, for example, emergency operation or emergency venting is possible. It is therefore possible for the user to directly actuate the valve device. However, it is also possible for the user to actuate the valve device by means of a control device.

[0037] In a preferred embodiment, the valve device is a screw-in valve, i.e. a valve that can be screwed into a particular area of ​​the pump device. Preferably, the valve device is a two-way valve.

[0038] It is contemplated that the venting valve could be located in various locations, for example between the pump head and the nozzle arrangement, however, it may be advantageous to locate it at the highest point of the pump head, particularly in a direct nozzle mounted configuration.

[0039] In a preferred embodiment, the valve device has a seat seal, in particular a soft seat seal, and in addition, the valve device is particularly preferably designed such that the dead space is small.

[0040] This design has the (constructive) advantage that the internal volume of the valve (i.e. the part in contact with the medium) is as small as possible, thus preventing undue influence on the efficiency and dosing accuracy of the pumping device.

[0041] Thus, a pump with a very small "damage space" between the diaphragm and the nozzle is achieved. In this way, accuracy and reliability (especially with regard to venting) can be improved.

[0042] In a further preferred embodiment, the valve device is arranged in an area of ​​the pump device, in particular in an area of ​​the product chamber of the pump device, and / or the valve device is arranged in the upper part, in particular in the highest area (with respect to the medium to be conveyed) of the pump device and / or the product chamber. The highest area is understood to be the area that is arranged highest in the vertical direction or in the direction towards the center of the earth compared to other areas. Preferably, the valve device is arranged in such a way that the gaseous medium can collect in the area of ​​the valve device.

[0043] In this way, venting of the pump device is possible in a particularly advantageous manner, in particular air bubbles can be removed or expelled from the pump device in a very advantageous manner.

[0044] In a further preferred embodiment, a line for conducting the vent gas and / or liquid (especially the liquid to be transported) is connected to the valve device (especially to the outlet of the valve device). In principle, it would also be possible to carry out the vent to the environment. However, it is proposed to recirculate these, especially with regard to the preservatives. In this case, both gas and liquid can be discharged during the venting process. For this reason, the line serves at least in part to return these media, especially liquid media, to the circuit and / or to the pump device. As will be explained in more detail below, the discharged gas and / or liquid can be sent to a container via this line.

[0045] In a further preferred embodiment, the device has a measuring reservoir and / or a measuring device for detecting the level of the liquid and / or gaseous medium, preferably the above-mentioned line opens into this measuring reservoir. The measuring reservoir can be, for example, a measuring burette, i.e. a vessel with a measuring graduation. In general, in the context of the present invention, a measuring reservoir is understood to be a device that has a receiving volume for receiving a liquid medium and further allows this volume to be determined. The measuring reservoir can also allow liquid to pass through the measuring reservoir.

[0046] In a further advantageous embodiment, the device has a receiving chamber for at least temporarily receiving the liquid medium discharged from the pump device via the valve device, said receiving chamber preferably communicating with the above-mentioned line connected to the valve device, said receiving chamber preferably being formed by the above-mentioned measurement reservoir.

[0047] Preferably, the quantity of discharged gas or liquid is conveyed via a line to a calibration or measurement reservoir on the suction side, which is preferably designed in such a way that the gas phase can escape and the liquid phase can be re-fed or fed to the process and / or pumping device.

[0048] Preferably, therefore, the device, in particular the measurement reservoir, has a separation device so that the gas and liquid components of the medium escaping via the vent valve can be separated. This separation device can also be formed by the shape of the measurement reservoir itself.

[0049] Preferably, the measuring vessel has a filling level measuring device. Particularly preferably, the measuring vessel has a float device, in particular for level measurement. However, other sensors suitable and intended for determining the filling level in the measuring vessel are also possible.

[0050] In a further preferred embodiment, the device has an evaluation device for evaluating and / or determining the filling level (of the measurement vessel). For example, an image recording device such as a camera can be used to monitor the filling level in the measurement vessel. The filling level measuring device can also output data that can be used to control the pump device and / or the valve device.

[0051] In a further preferred embodiment, the device comprises a sensor device for detecting at least one parameter characteristic of the substance or medium delivered by the valve device, for example a flow measuring device can be provided in the line leading to the valve device, so that the gas and / or liquid medium flowing through the line can be determined in terms of flow rate.

[0052] In addition, a measuring device can be provided which outputs a parameter characteristic of whether the escaping medium is a gaseous or liquid medium.

[0053] Preferably, a temperature sensor can be used here (as measuring or sensor device). This temperature sensor is preferably kept at a suitable temperature (in particular electronically controlled). As soon as the liquid medium passes from the valve device and reaches the temperature sensor, the temperature of the sensor changes, since the temperature of the liquid is preferably somewhat lower than that of the sensor. In this way, the temperature sensor can provide a signal for the control system to detect backflow medium.

[0054] However, other measurement methods are contemplated, such as ultrasonic measurement or mass flow detection, however, as mentioned above, thermal based flow detection methods are preferred.

[0055] Based on the measurements of this sensor device it can be determined whether gas is leaking from the pump or whether liquid is already leaking.

[0056] Therefore, particularly preferably, a sensor device is provided, in particular a sensor device is installed in said line, which monitors the vent function. For example, the vent process should continue as long as gas flows past the sensor device. If liquid flows along the sensor device, the vent has been successfully completed.

[0057] In a further preferred embodiment, the measurement reservoir has an inlet for liquid and / or an outlet for liquid, which outlet is connected to a pump device. Preferably, the measurement reservoir further comprises a discharge device for discharging the gaseous medium. The discharge device can comprise a filter device for filtering the discharged medium.

[0058] The measuring vessel or measuring burette on the suction side preferably has a float, as mentioned above, by means of which the level in the vessel is monitored and in particular allows the calculation of the actual input of the pump in normal operation.

[0059] During pump venting, for example, when the pump device is working and the valve device is open, the pump sucks in liquid but expels gas through the solenoid valve, so that the level in the measurement vessel drops. In this operation procedure, when the pump venting in the venting operation is successfully completed, the amount of liquid sucked in by the pump is balanced with the amount supplied to the measurement vessel through the valve and line or return line. In this state, the level in the measurement vessel remains stable.

[0060] In a further preferred embodiment, the device comprises at least one temperature measuring device for detecting the temperature of at least one element of the pumping device. Preferably, the corresponding element is the pump head and / or the piston and / or diaphragm part of the pumping device, or generally a moving element of the pumping device that is in direct contact with the pumped medium. High temperatures (however, temperatures below 45° C.) increase the decomposition process of dimethyl dicarbonate and thus the formation of a gas phase.

[0061] Particularly preferably, the above-mentioned control device also controls the valve device taking this measured temperature into account, for example the control device can shorten the time between periodic vent strokes and / or the time between opening of the valve.

[0062] The present invention is further directed to a method for preserving a beverage, wherein the flow rate of liquid flowing through a beverage line is determined by measuring device means, a preservative, in particular a dialkyl dicarbonate, is conveyed to the beverage line by pumping device means, a delivery line opening into the beverage line and the pumping device delivers the preservative through the beverage line, the pumping device being controlled as a function of the flow rate determined by the measuring device means.

[0063] According to the invention, the pumping device is at least temporarily vented by means of a venting device, the venting being carried out by means of a controlled valve device. It is therefore also proposed on the method side that a controlled venting of the pumping device takes place in at least some operating states.

[0064] Particularly preferably, the pump device can be operated in different operating states: in a preferred manner, the vent device is cyclically controlled in an operating mode and / or the valve device is controlled in an operating mode taking into account the pumping action of the pump device.

[0065] For example, during the dosing operation, it is possible to periodically open a valve device, in particular a solenoid valve, in order to ensure the evacuation of air bubbles that occur during the operation.Preferably, this opening of the valve device takes place before the following dosing stroke, preferably at a predefined time period before this dosing stroke.

[0066] Preferably, the predetermined period of time is less than 0.5 seconds, preferably less than 0.3 seconds, preferably less than 0.2 seconds, preferably less than 0.1 seconds, preferably less than 0.08 seconds, preferably less than 0.06 seconds, preferably less than 0.05 seconds, preferably less than 0.04 seconds, preferably less than 0.03 seconds, preferably less than 0.02 seconds.

[0067] Preferably, this period is greater than 1 / 100th of a second, more preferably greater than 2 / 100ths of a second, more preferably greater than 3 / 100ths of a second.

[0068] In this way, operation of the valve at reduced pressure or at low internal pump pressures is possible, so that the dosing accuracy of the pumping device is only slightly affected and, on the other hand, the solenoid valve or the forces required for its operation are low.

[0069] Additionally, venting can be performed during breaks in production in operating modes where production is occurring but no pumping is taking place to introduce preservatives into the beverage line, in which case the valve arrangement can be opened periodically to ensure that any air bubbles that may form are removed and / or to allow for the required dosage accuracy on the next pump stroke.

[0070] Furthermore, the device preferably operates in an operating mode heating and / or at least temporarily in this mode, in particular as a waiting position before the arrival of a further batch of beverage to be filled. In this operating mode, periodic automatic pump strokes are preferably triggered when the valve is open. In this operation, the pump preferably remains ready despite the formation of air bubbles in the pump head, which are periodically expelled in this operation.

[0071] As mentioned above, an increase in heat transfer to the pump head may occur when exposed to higher temperatures, which increases the decomposition process and therefore the formation of gas bubbles. Preferably, the interval between periodic venting strokes (as mentioned above in the operating mode heating) is now changed, in particular shortened. Preferably, the system control allows an operating mode venting, which can be selected manually or typically by user intervention, in which the pump device operates with the valve open for (conveniently fixed) time intervals. In this operating mode, an intensive venting or degassing process is performed.

[0072] In a further preferred method, the gaseous and / or liquid medium discharged through the valve device is passed into a container, in particular a measurement container. In a further preferred method, the medium discharged through the valve device is analyzed to determine whether it is a gaseous or liquid medium.

[0073] In a further preferred method the temperature of at least one element of the pump device is at least temporarily determined.

[0074] Further advantages and embodiments can be seen in the accompanying drawings. [Brief description of the drawings]

[0075] [Figure 1] 1 shows a schematic diagram of an apparatus according to the invention; [Diagram 2] FIG. 1 shows a detailed view of the venting process. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0076] Figure 1 shows a device 1 for storing beverages according to the Applicant's internal prior art, where reference number 10 designates a beverage line which supplies a liquid, in particular a beverage, to be filled into containers to a filling machine 20. Reference number 2 designates a flow measuring device which determines or measures the flow rate of the beverage through the beverage line 20. This flow measuring device 3 outputs a control signal S to a control device 14 which controls a pump device 4 taking into account this control signal S.

[0077] The pump device 4 delivers the preservative from a reservoir 8 via a nozzle head 6 into a beverage line 10, more precisely here into a curved region 10a of the beverage line 10. Reference number 5 denotes a delivery line of which the nozzle head is preferably also a component.

[0078] Figure 2 shows a more detailed view of the invention. Here again a pumping device 4 is shown, which in this case is a diaphragm pump, in particular a dosing pump.

[0079] A valve device 22 is provided in the (preferably) upper region of the pump device and is a component of the vent device generally designated 2. As mentioned above, the valve device 22 is preferably a solenoid valve which can be opened and closed under the control of a control device 30 (shown only diagrammatically).

[0080] A vent line 24 is connected to this solenoid valve arrangement 22. Reference number 3 indicates a measuring device which determines whether a gaseous or liquid medium is flowing in this vent line 24. In this way it can be determined whether the venting has been successful or whether air or gas in general is still present in the pump arrangement 4.

[0081] The line 24 preferably opens into a measuring reservoir 28 which has a float device 34 and a scale by which the level of the liquid in the measuring device 3 or in the measuring reservoir 28 can be ascertained.

[0082] Reference number 32 denotes an optional sensor device for detecting the filling level of the liquid in the measuring vessel. Data from this measuring device 32 is also preferably used for controlling the valve device 22 and / or for controlling the pump device 4.

[0083] Reference number 16 denotes an optionally available temperature measuring device, which measures the temperature of at least one element of the pumping device 4, in particular the temperature in the region of the pump head. Depending on this temperature, the degassing behavior in the liquid to be dispensed may also change. Therefore, preferably, data from this temperature measuring device 16 is also preferably used for controlling the valve device 22 and / or the pumping device 4.

[0084] In addition, data relating to the operation of the pump arrangement 4 itself is preferably also used for controlling the valve arrangement 22. For example, data representative of the position of a pump element, such as a pump piston, can be used. This data is also preferably used for controlling the valve arrangement 22. For example, the valve arrangement 22 can always be operated at a certain time, for example just before another pump stroke occurs, as described above.

[0085] Preferably, dialkyl dicarbonate is used as the preservative. Very preferably, dimethyl dicarbonate is used, and even more preferably, dimethyl dicarbonate with a purity of more than 99.8% is used as the preservative. In a further embodiment of the invention, dimethyl dicarbonate stabilized by an appropriate process is used.

[0086] Such a method is known, for example, from EP 2 013 160, as the use of phosphorus compounds from the series of phosphorus oxides, phosphorus oxyacids and their derivatives. EP 2 016 041 describes the use of at least one protic acid selected from inorganic and organic carboxylic acids and their derivatives to stabilize the dialkyl dicarbonate against chemical and thermal decomposition reactions, the organic carboxylic acids 20 being saturated and mono- or polyunsaturated aliphatic monocarboxylic acids and saturated and mono- or polyunsaturated aliphatic di- and polycarboxylic acids, in the case of their derivatives being hydroxamic acids, hydroxycarboxylic acids, aldehydes and keto acids, the protic acid or mixtures thereof being used in an amount of 0.01 to 100 000 ppm relative to the dialkyl dicarbonate or mixtures thereof.

[0087] In a further embodiment of the present invention, dimethyl dicarbonate is preferably used in a mixture with a phosphorus compound such as a phosphate, even more preferably trimethyl phosphate or phosphoric acid. Preferably, the phosphorus compound 30 is used in an amount of 0.01 ppm to 1000 ppm based on the total amount of the mixture of dimethyl dicarbonate and phosphorus compound.

[0088] The applicant reserves the right to claim that all features disclosed in the application are essential to the invention, provided that they are new, either individually or in combination, compared to the prior art. It is further noted that the figures also depict features that may be advantageous in themselves. Those skilled in the art will immediately recognize that certain features depicted in the figures may also be advantageous, even without adopting additional features from the figures. Furthermore, those skilled in the art will recognize that advantages may also be obtained from the combination of several features depicted in individual figures or in different figures. [Explanation of symbols]

[0089] 1 device 2 Venting device 3. Measuring Equipment 4. Pumping equipment 5 Delivery Line 6 Nozzle Head 8 Reservoir 10 Beverage Line 10a Curved Area 12 Monitoring equipment 14 Control device 16 Temperature detection device 18 Temperature measuring device 20 Beverage Line 22 Valve gear 24 Line / Vent Line 28 Measuring vessel 30 Control device 32 Sensor device 34 Float Device

Claims

1. A device (1) for preserving a beverage, comprising a measuring device (3) suitable for and intended to determine a flow rate of a liquid flowing through a beverage line (10), a pumping device (4) for conveying a preservative, in particular a dialkyl dicarbonate, into said beverage line (10), said pumping device (4) being controllable as a function of the flow rate determined by said measuring device (3), and a venting device (2) for venting said pumping device (4), The apparatus (1), characterized in that the vent device (2) comprises a valve device (22).

2. 2. The device (1) according to claim 1, characterized in that the valve device (22) is a solenoid valve (22).

3. 2. The device (1) according to claim 1, characterized in that the device (1) comprises a control device (30) for controlling the valve device (22).

4. Apparatus (1) according to any one of claims 1 to 3, characterized in that the apparatus (1) comprises a monitoring device (12) for monitoring the venting process.

5. The device (1) according to any one of claims 1 to 3, characterized in that the valve device (22) can also be actuated manually and / or by user manipulation.

6. the valve device (22) being arranged in the region of the pump head of the pump device (4), and / or the valve device (22) is arranged in the highest region of the pump device (4), Device (1) according to any one of claims 1 to 3.

7. Apparatus (1) according to any one of the preceding claims, characterized in that a line (24) conducting vent gas and / or liquid is connected to the valve device (22).

8. The device (1) according to any one of the preceding claims, characterized in that the device (1) comprises a measuring reservoir (28) for detecting the level of a liquid medium and / or a gaseous medium.

9. 9. The device (1) according to claim 8, characterized in that a line (24) conducting a gaseous and / or liquid medium of a vent connected to the valve device (22) opens into the measurement reservoir (28).

10. The device (1) according to any one of claims 1 to 3, characterized in that the measurement reservoir (28) has an inlet for liquid and / or an outlet for liquid, preferably the outlet communicating with the pump device (4).

11. The device (1) according to any one of claims 1 to 3, characterized in that the device (1) comprises at least one temperature measuring device (18) for detecting the temperature of at least one element of the pump device (4).

12. The flow rate of the liquid flowing through the beverage line (10) is determined by a measuring device (3), A preservative, in particular a dialkyl dicarbonate, is conveyed to the beverage line by a pump device (4), a delivery line opening into said beverage line (10) and said pump device (4) delivering a preservative through said beverage line (10); the pumping device (4) being controlled as a function of the flow rate determined by the measuring device (3), 1. A method for preserving a beverage, comprising: The pump device (4) is at least temporarily vented by a vent device (2); The venting is performed by a controlled valve device (22). A method comprising:

13. In an operating mode, the valve device (22) is periodically controlled; and / or in the operating mode, the valve device (22) is controlled taking into account the pumping action of the pump device (4).

13. The method of claim 12.

14. The gaseous and / or liquid medium discharged via the valve device (22) is passed into a container, in particular a measurement container (28), and / or the medium discharged through the valve device (22) is analyzed to determine whether it is a gaseous medium or a liquid medium.

13. The method of claim 12.

15. 15. The method according to any one of claims 12 to 14, characterized in that the temperature of at least one element of the pump device (4) is determined at least temporarily.

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