EP0979206B1 - Method and device for filling barrels - Google Patents

Abstract

Disclosed is a method for filling barrels (4), specially kegs, with liquids, wherein at least one gas is dissolved. The barrel (4) is pre-stressed using a gas before the liquid is filled. Liquid is then fed into the barrel (4) by means of a filling valve (2) pertaining to a filling station (1) and connected to a feed line (3, 8). During filling, the pre-stress gas contained in the barrel (4) is evacuated. So as not to impair the product, the pre-stress gas in the barrel (4) is pre-stressed at only a partial pressure which corresponds approximately to the saturation pressure of the CO2 or N2 which is dissolved in the filled liquid. Said partial pressure is lower than the maximum product pressure occurring in the feed line (8) prior to the filling valve (2).

Description

The invention relates to a method for filling containers, especially kegs, with liquids in which at least one Gas is dissolved, the container before filling the Liquid is biased with a biasing gas, then the Container via a connected to a supply line Filling valve fed to a filling station and during liquid of the filling process, the biasing gas contained in the container is dissipated, and a device for performing this Procedure.

Carbonated beverages, such as beer, only keep their CO ₂ in solution if the partial pressure of the gas CO ₂ above the liquid is at least as high as the saturation pressure in the liquid. If the gas pressure above the liquid is below the saturation pressure, the liquid loses CO ₂ , but if the gas pressure is significantly higher, there is a risk that additional CO ₂ will dissolve. The gas absorption is dependent on the differential pressure between the saturation pressure in the liquid and the partial pressure above the liquid, the time available for gas exchange, which is usually equivalent to the filling time of the container, and the size of the gas exchange surface, i.e. the Liquid surface. Due to the turbulence in the liquid during the filling process, the risk of gas absorption during filling is considerably increased. The gas exchange between the liquid and the superimposed gas atmosphere affects not only the CO ₂ , but also other gases present in the gas atmosphere, in particular oxygen, which is absorbed by the liquid according to the same laws. However, oxygen is an important factor for the quality of the product in liquids that can be damaged by microorganisms or whose durability is endangered by the oxidation of liquid components.

In order to get the product into the container through a valve, be it a bottle or a barrel, a differential pressure between the supply line and the interior of the container is necessary. The size of the differential pressure determines the inflow speed of the product. Typically, the product is filled with turbulence at an initially low speed to avoid increasing the surface area, which is then slowly increased. For this purpose, the container is pretensioned with a gas pressure that is significantly above the saturation pressure of the gas dissolved in the liquid. The liquid itself is also kept at this pressure level by tanks or pumps and fed to the filling machine. After the container has been pretensioned to the pressure of the liquid supplied, a connection is established between the container and the supply line of the filling material. Controlled draining of the prestressing gas in the container enables the filling material to flow into the container. The differential pressure that builds up determines the flow rate of the liquid. It is also known that the gas outlet is throttled towards the end of the filling, and as a result the differential pressure between the interior of the container and the supply line decreases. Towards the end of the filling process, this results in a reduction in the filling quantity per unit of time, which enables precise switching off when a target quantity is reached. This known method is referred to as "return gas control". The advantage of this regulation is that the gas pressure above the liquid is always above the saturation pressure of the CO ₂ gas.

The preload pressure to be set is determined by experience. At the beginning of the filling process, the product is said to lose CO ₂ due to turbulence that results in local negative pressures. This creates a deliberate artificial foam on the surface of the liquid, the bubbles of which only contain the released CO ₂ and thus protect the product from contact with the oxygen-containing gas atmosphere above. During the further filling process, the turbulence and with it the local negative pressure disappear. The product absorbs CO ₂ again during the remaining filling time. The trick is, depending on the CO ₂ content, temperature, container size and calculated filling time, to achieve a balance between CO ₂ loss and recovery.

In addition to the fact that the container must be biased far above the saturation pressure in the return gas control and the draining must be carried out in a controlled manner in order to achieve a controlled filling speed, the reduction of the filling speed in the last filling section is problematic. If the liquid inlet pressure remains constant, the flow rate can only be reduced if the differential pressure is reduced. In the known methods, the gas outlet is throttled (or in extreme cases prevented) and waited until the rising fill level has reduced the back pressure to the desired value by compressing the remaining gas volume in the container. This period can be significant, especially for beer kegs. A 50 l keg usually has an inlet cross-section DN21 and a maximum filling speed of 3 l / sec at a differential pressure of 0.8 bar. If the keg is filled with 35 l, 15 l gas space must be compressed by 0.7 bar to reduce the speed. For this, 15 x 0.7 = 10.5 l of liquid and, due to the slowing filling speed, about 8 seconds of filling time are required. Fast, precise regulation is therefore not possible, particularly in the case of possibly fluctuating inlet pressures. The situation is even more critical if not only one gas (for example CO ₂ ) but two gases (for example CO ₂ and N ₂ ) are deliberately dissolved in the product. Nowadays, N ₂ is added to beer because it has a foam-stabilizing effect. The best example of this is stout beer, whose creamy, long-lasting foam is caused by the dissolved N ₂ released when tapped. However, N ₂ and CO ₂ have completely different solubilities and saturation pressure curves. While CO ₂ easily dissolves and is difficult to get out of solution, it is extremely difficult to get N ₂ into solution at all and very easy to remove N ₂ even with the slightest turbulence. The balance between degassing at the start of filling and resumption of the lost gas during filling is almost impossible to find in 2-gas systems. The quality of the product to be filled is therefore fluctuating. Attempts are made to compensate for this by keeping the ratio of the gas atmosphere CO ₂ to N ₂ different from the proportion of the dissolved gases. However, this compromise is only valid for one temperature or one container size and only for one product supply pressure. It is impossible to master these many factors and their tolerances in terms of control technology.

Another disadvantage of the return gas control is that the container has to be prestressed with gas, usually CO ₂ , far beyond the saturation pressure in order to achieve a pressure drop that is still above the saturation pressure even during the maximum lowering of the internal pressure during the filling process of the gas. Since the gas is then released into the atmosphere, this also results in increased consumption of the greenhouse gas CO _{2 in} addition to energy consumption.

From US-A-3 395 739 a bottle filling system is known which cooperates with a carbonation plant. Behind the A pump is installed in the carbonation system, which Beverage pressure significantly above the saturation pressure of the liquid raises to improve the solubility of carbonic acid. A cooler (or a high-speed heating system is connected to the pump with subsequent cooler) to the Should reduce the saturation pressure of the solution. By a Pressure maintaining device should nevertheless be a higher pressure than Saturation pressures are maintained, taking the liquid to the fill head at a pressure of 241.36 to 275.84 KPa (35 to 40 psi). The filling takes place with a pressure drop via the valve of the Filling head, reducing the pressure to approximately 68.96 KPa (10 psi) before the liquid is biased to about 41.37 KPa (6 psi) Bottle is filled. The valve of the filling head is however no regulation assigned. This means that the Filling pressure in front of the bottle is higher than that Preload pressure and this due to the pressure drop in the valve Pressure is relieved. The pressure reduction is constant, however that the product pressure both before the pressure relief valve as well after the pressure relief valve is constant. This means, that there is no pressure increase during the filling process. A targeted adjustment of the filling speed depending on of the level in the container is therefore not possible.

The object of the invention is therefore to a gentle filling enable and reduce the consumption of bias gas.

This object is essentially achieved with the invention solved that the biasing gas in the container only to one about the saturation pressure of one of the bottled ones Partial pressure corresponding to liquid dissolved gases is biased below that in the supply line product pressure applied to the filling valve.

The container is preloaded as far as possible exactly to the product pressure directly at the filling valve, to inject the product when the filling valve is opened to prevent in the container. Instead of as with the return gas control the differential pressure for the filling process by lowering the gas pressure level in the barrel and the product supply pressure According to the invention, keeping constant is proposed the internal gas pressure to generate the necessary differential pressure to keep constant in the container and the product supply pressure increase at the inlet of the container.

There are basically two ways of supplying the product in the supply line. This can either, as with a first embodiment of the invention provided with a or even slightly under the preload pressure in the container lying pressure or with a higher pressure as it provided according to a second embodiment of the invention is.

Common to both embodiments is that of filling differential pressure to be applied between product supply and Interior of the container via a pressure control device (in the Supply line instead of in the return gas line) for each filling station is applied controllably. This can be done either a pressure increasing or a pressure reducing unit. This means that any desired differential pressure to the inside of the container can be achieved adjust individually in the shortest possible time, so that in In contrast to the return gas control, a delay-free control is achieved.

The gas inside the container can then be easily removed Overflow valve pushed out by the inflowing product become. The previously expensive control engineering Apparatus are no longer necessary for this. With liquids with several dissolved gases the optimal gas composition can be can be set within the container, because during the Filling process over the entire time an equal pressure in the The inside of the container prevails. With conventional return gas control had the changing pressures inside the container during the Filling process in the different filling phases different Gas exchange behavior and thus an influence the product quality. This is through the invention completely fixed.

According to a preferred development of the invention, the Preload pressure within the container according to the Saturation pressure set after filling. background this inventive idea is the fact that beer kegs before the filling for sterilization can be steamed and the cold Product is filled into the still hot container. Here become 50 l in approx. 12 kg of metal at a temperature of 100 ° C Beer filled at a temperature of approx. 3 ° C. It turns out a mixing and equalizing temperature, which is the temperature of the product in the container by approx. 4 ° C compared to the supply temperature elevated. Of course, this changes the Saturation pressures of the dissolved gases, so that according to the invention value to be set to that of the product in the filled Containers must correspond. This question has been asked in the past never posed because the back pressure is always significantly above the saturation pressure.

An apparatus for performing the above Procedure with a filling station, which is via a feed line product liquid to be filled into the container and from the escaping from the container via a return gas line Bias gas is discharged, according to the invention in the Filling station a pressure control device to determine the Filling pressure at the filling station. This allows the Product pressure at each filling station depending on completely independent of the filling quantity or filling level Feed pressure of the product to be filled and independent of the other filling stations possibly provided on the filling machine can be set. In many cases also a simplification of the filling machines usually upstream pressure tanks and their control, since this also without influencing the product to the optimal gas mixture according to the conditions at saturation pressure can be adjusted.

The pressure control device is expediently a Pressure sensor to determine the product pressure on the assigned to individual filling station.

In a preferred embodiment of the invention Pressure control device a pressure increasing unit, preferably a frequency controlled pump, with which everyone Desired differential pressure to the inside of the container within Can produce fractions of a second.

As an alternative to that provided at the individual filling station Pressure increasing unit can also be central, for example attached pressure booster unit and an additional one on each Filling station arranged pressure reducing unit, especially in controllable pressure reducing valve may be provided. Problematic here is that at low flow rates because of high differential pressures between product supply pressure before Pressure reducing station and in the container behind the pressure reducing station only small nominal sizes can be released by which the product with due to the high pressure difference Valve seat squeezed through at high flow rates, in the subsequent extended pipeline with on average flow at low speed. With this "squeezing" the easily soluble gas can be released and lather up the liquid and its composition change.

In further development of this inventive idea are therefore under Under certain circumstances, compensators connected in parallel are provided which prevents excessive gas release.

According to a preferred embodiment of the invention Return gas line provided an overflow valve through which the Return gas is discharged.

Further training, advantages and possible applications of Invention also result from the following description of exemplary embodiments and the drawing. Thereby everyone described and / or illustrated features for himself or in any combination the subject of Invention, regardless of its summary in the Claims or their relationship.

Show it:

Fig. 1

a schematic representation of a filling station according to a first embodiment of the invention and

Fig. 2

a schematic representation of a filling station according to a second embodiment of the invention.

The filling station 1 shown in Fig. 1 consists essentially from a filling valve 2, which via a supply line 3 a liquid, such as beer, in which gases are dissolved becomes. On the filling valve 2 is a container, in particular a Keg 4 put on, filled with the product liquid shall be.

One of the individual filling stations 1 is located in the feed line 3 assigned pressure booster pump 5 provided via a Frequency converter 6 depending on the one Pressure sensor 7 determined pressure in the line section 8 to the filling valve 2 and the gas pressure in the keg 4 is controlled.

In the keg 4, a riser pipe 9 is provided, which with a Return gas line 10 of the filling valve 2 is connected. The Return gas line 10 leads to an overflow valve 11, via the access to a return gas outlet 12 is controlled. To the Return gas line 10 is also a bias gas line 13 connected, which can be shut off via a valve 14.

To fill the container 4, this is first biased via the biasing gas line 13 and the return gas line 10 with a biasing gas, in particular CO ₂ . In the case of certain liquids, for example stout beer, the biasing gas can also be a composition of several gases, such as CO ₂ and N ₂ . The preload pressure in the keg 4 is only at a partial pressure corresponding approximately to the saturation pressure of the CO ₂ (or N ₂ ) in the beer, which is approximately at the product pressure in the line section 8 of the supply line 3 in front of the filling valve 2. The back pressure of the biasing gas in the keg 4 corresponds to the saturation pressure of the dissolved gas after filling the keg 4, ie in the filled container. It is taken into account here that the beer filled at a temperature of approximately 3 ° C. warms by approximately 4 ° C. in the keg 4 which is usually steamed before filling and is therefore hot at approximately 100 ° C. The change in saturation pressure caused by this is already taken into account when setting the original preload pressure.

After closing the bias gas valve 14, the filling valve 2 opened, there is initially equal pressure. After switching on the pump 5, which is started via a "ramp", the Filling speed increased slowly, not to oversize Causing turbulence. That from the supply line 8 through the annular gap 15 in the filling valve 2 conveyed into the keg 4 Beer pushes the preload gas contained in the keg 4 through the Riser pipe 9 out of the keg 4. The bias gas escapes via the overflow valve 11 into the return gas outlet 12.

The differential pressure desired between the inside of the keg The product supply pressure and the preload pressure can be set via the pump 5 can be produced within fractions of a second, so that the desired filling speed exactly the filling height accordingly, without delay and individually for each individual filling station 1 can be controlled.

The second embodiment shown in FIG. 2 corresponds essentially the embodiment of FIG. 1, so that matching elements designated with the same reference numerals and their detailed description again is waived.

The main difference from the first embodiment lies 2 in that in the Filling station 20 via a central pressure increasing unit 21 in the supply line 3 is set an increased pressure. Everyone individual filling station 20 is a pressure reducing valve 22 assigned that the pressure at the filling valve 2 to that for the Product supply at the filling station 20 desired supply pressure reduced, which is detected via the pressure sensor 7. At the Opening the filling valve 2 should also first equal pressure here between the feed line section 8 and the inside of the Container 4 prevail and the one required for beer production Differential pressure then via the pressure reducing valve 22 below Taking into account that of the pressure meter 7 in the supply line 8 determined pressure can be set. Should in the Supply line 8, however, still open when the filling valve 2 is opened There is increased pressure because of the incompressibility the liquid in the line section 8 not critical.

To avoid that when "squeezing" the under high Product liquid under pressure in the supply line 3 22 gas released through the valve seat of the pressure reducing valve are not parallel to the pressure reducing valve 22 compensators shown in detail provided. The rest Operation corresponds to that of embodiment 1. Here too can the differential pressure between the product line 8 and the Preload pressure in the keg 4 through the pressure reducing valve 22 very much can be set quickly.

An essential aspect of both embodiments of the invention is that the pretension in the keg 4 only has to be set to a partial pressure corresponding approximately to the saturation pressure of the CO ₂ (or N ₂ ) in the beer and is thus far below the conventionally set pretension pressure. Via the pressure control unit 5 or 22 assigned to each individual filling station 1, 20, it is possible to control the filling speed in the keg 4 without delay, so that filling with previously unattainable product protection is made possible. Damage due to unwanted loss or absorption of CO ₂ or the absorption of oxygen from the bias gas is avoided and the product quality is significantly improved with lower energy consumption and CO ₂ emissions.

Reference symbol list:

1

Filling station

2nd

Filling valve

3rd

Supply line

4th

Keg

5

Booster pump

6

frequency converter

7

Pressure transducer

8th

Line section

9

Riser pipe

10th

Return gas line

11

Overflow valve

12th

Back gas outlet

13

Leader line

14

Valve

15

Annular gap

20th

Filling station

21

Pressure increasing unit

22

Pressure reducing valve

Claims (12)

1. Method for filling barrels (4), especially kegs, with liquids, in which at least one as is dissolved, wherein the barrel (4) is pre-stressed with a pre-stress gas before being filled with liquid, wherein then liquid is fed to the barrel (4) by means of a filling valve (2) of a filling station (1,20), connected to a feed line (3, 8), and wherein the pre-stress gas contained in the barrel (4) is removed during the filling process, characterized in that the pre-stress gas in the barrel (4) is only pre-stressed to a partial pressure, roughly corresponding to the saturation pressure of one of the gases dissolved in the liquid being filled, especially CO₂ or N₂, which lies below the maximum product pressure applied in the feed line sect on (8) upstream the filling valve (2), and that the differential pressure between product input and inside of the barrel necessary for performing the filling is introduced by means of a pressure control device (5, 22) in a controllable manner for each filling station (1, 20).
2. Method according to claim 2, characterized in that the product input into the filling station (1) is conducted through the feed line (3) upstream the pressure control device (5, 22) at a pressure, which lies approximately at or slightly below the pre-stressing pressure in barrel (4).
3. Method according to claim 1, characterized in that the product input into the filling station (20) is produced through feed line (3) upstream the pressure control device (5, 22) at a pressure, which is higher than the pre-stressing pressure in barrel (4).
4. Method according to any of claims 1 to 3, characterized in that the pre-stress gas provided in the barrel (4) is forced out from the barrel (4) by the inflowing product.
5. Method according to any of claims 1 to 4, characterized in that the prestress pressure in the barrel (4) is adjusted such that it corresponds roughly to the saturation pressure of the dissolved gas in the filled barrel (4).
6. Device for carrying out a method according to any of claims 1 to 5 with a filling station (1, 20) with a feed line (3, 8), by which product liquid is supplied for filling a barrel (4) provided at the filling station (1, 20), and with a return gas line (10), by which pre-stress gas escaping from the barrel (4) is discharged, characterized in that a pressure control device (5, 22) for establishing the filling pressure in the feed line section (8) of filling station (1, 20) is provided at the filling station (1, 20), and that a pressure sensor (7) for establishing the product pressure in the feed line section (8) of filling station (1, 20) is assigned to the pressure control device (5, 22).
7. Device according to claim 6, characterized in that the pressure control device is a pressure increasing unit (5).
8. Device according to claim 7, characterized in that the pressure increasing unit is a preferably frequency-controlled pump (5).
9. Device according to claim 6, characterized in that a central pressure increasing unit (21) is provided in feed line (3) and that a pressure reducing unit (22) is assigned to each filling station (20).
10. Device according to claim 9, characterized in that the pressure reducing unit is a preferably controllable pressure reducing valve (22).
11. Device according to claim 9 or 10, characterized in that compensators are provided parallel to the pressure reducing unit (22).
12. Device according to any of claims 6 to 11, characterized in that an over low valve (11) is provided in the return gas line (10), by which the return gas is discharged.

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