EP0979206A1

EP0979206A1 - Method and device for filling barrels

Info

Publication number: EP0979206A1
Application number: EP98916983A
Authority: EP
Inventors: Volker Till
Original assignee: GEA Till GmbH and Co
Current assignee: KHS Till GmbH
Priority date: 1997-04-29
Filing date: 1998-03-18
Publication date: 2000-02-16
Anticipated expiration: 2018-03-18
Also published as: JP3335181B2; JP2000511139A; WO1998049088A1; EP0979206B1; DE29712148U1; ES2161047T3; ATE202325T1; DK0979206T3; US6230763B1

Abstract

Disclosed is a method for filling barrels (4), specially kegs, with liquids, wherein at least one gas is dissolved. The barrel (4) is prestressed 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 prestress gas contained in the barrel (4) is evacuated. So as not to impair the product, th eprestress gas in the barrel (4) is prestressed at only a partial pressure which corresponds approximately to the saturation pressure of the CO>2< or N>2< 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

Method and device for filling containers

The invention relates to a method for filling containers, in particular kegs, with liquids in which at least one gas is dissolved, the container being pre-stressed with a biasing gas before filling the liquid, then the container via a filling valve of a filling station connected to a supply line Liquid supplied and the bias gas contained in the container is removed during the filling process, as well as a device for performing this method.

Carbonated beverages, such as beer, only keep their C0 ₂ in solution if the partial pressure of the gas C0 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 C0 ₂ , but if the gas pressure is significantly higher, there is a risk that additional C0 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 liquid and the However, 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 C0 ₂ gas.

The preload pressure to be set is determined by experience. At the beginning of the filling process, the product should lose C0 ₂ due to turbulence that results in local negative pressures. This creates a deliberate artificial foam on the liquid surface, the bubbles of which only contain the released C0 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 resumes C0 ₂ during the remaining filling time. The trick is to achieve a balance between C0 ₂ loss and recovery depending on the C0 ₂ content, temperature, container size and calculated filling time.

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 1 keg usually has an inlet cross-section DN21 and a maximum filling speed of 31 / sec at a differential pressure of 0.8 bar. If the keg is filled with 35 1, 15 1 gas space must be reduced by 0.7 to reduce the speed be compressed bar. For this 15 x 0.7 = 10.5 1 liquid and due to the slowing filling speed about 8 seconds filling time are required. Fast, precise regulation is therefore not possible, especially in the case of possibly fluctuating inlet pressures. The situation is even more critical if not only one gas (for example C0 ₂ ) but two gases (for example C0 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 C0 ₂ have completely different solubilities and saturation pressure curves. While C0 ₂ easily goes into solution and is difficult to get out of solution, it is extremely difficult to get N ₂ into solution at all and it is 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. An attempt is made to compensate for this by keeping the ratio of the gas atmosphere C0 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 must be biased far beyond the saturation pressure with gas, usually C0 ₂ , 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 then into the Atmosphere is released, in addition to the energy consumption, an increased consumption of the greenhouse gas C0 _{2 is} the result.

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

This object is essentially achieved with the invention in that the prestressing gas in the container is only biased to a partial pressure corresponding approximately to the saturation pressure of one of the gases dissolved in the filled liquid, which is below the product pressure present in the feed line upstream of the filling valve.

The pretensioning of the container is initially carried out as precisely as possible to the product pressure directly at the filling valve to prevent the product from being injected into the container when the filling valve is opened. Instead of producing the differential pressure for the filling process by lowering the gas pressure level in the barrel and keeping the product supply pressure constant, as in the case of the return gas control, it is proposed according to the invention to keep the internal gas pressure in the container constant in order to generate the necessary differential pressure and to keep the product supply pressure at the inlet of the container increase.

There are basically two ways of supplying the product in the supply line. This can take place either, as provided in a first embodiment of the invention, with a pressure at or even slightly below the pretensioning pressure in the container or with a higher pressure, as is provided in accordance with a second embodiment of the invention.

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

The gas inside the container can then be pushed out through the inflowing product using a simple overflow valve. The expensive control engineering devices that were usual up to now are no longer necessary for this. In the case of liquids with several dissolved gases, the optimal gas composition within the container can be set, since there is an equal pressure inside the container throughout the filling process. With conventional return gas control, the changing pressures inside the container during the filling process in the different filling phases resulted in different gas exchange behavior and thus an influence on the product quality. This is completely eliminated by the invention.

According to a preferred development of the invention, the pretensioning pressure within the container is set in accordance with the saturation pressure after filling. The background of this inventive concept is the fact that beer kegs are steamed for sterilization before filling and the cold product is filled into the still hot container. In this case, 50 liters of beer at a temperature of about 3 ° C. are filled into about 12 kg of metal at a temperature of 100 ° C. A mixing and compensation temperature is set which increases the temperature of the product in the container by approx. 4 ° C compared to the supply temperature. Of course, this changes the saturation pressures of the dissolved gases, so that, according to the invention, the value to be set corresponds to that of the product in the filled Containers must correspond. This question has never been asked in the past because the back pressure has always been significantly above the saturation pressure.

A device for carrying out the above-described method with a filling station, which is supplied with product liquid to be filled into the container via a supply line and from which bias gas escaping from the container via a return gas line, has, according to the invention, a pressure control device in the filling station for determining the filling pressure at the filling station on. As a result, the product pressure at each filling station can be set individually as a function of the filling quantity or filling level, completely independently of the supply pressure of the product to be filled and independently of the other filling stations which may be provided on the filling machine. In many cases there is also a simplification of the pressure tanks usually connected upstream of the filling machines and their regulation, since these can also be adjusted to the optimal gas mixture according to the conditions at saturation pressure without influencing the product.

The pressure control device is expediently assigned a pressure sensor for determining the product pressure at the individual filling station.

In a preferred embodiment of the invention, the pressure control device is a pressure increasing unit, preferably a frequency-controlled pump, with which any desired differential pressure to the inside of the container can be produced within fractions of a second.

As an alternative to that provided at the individual filling station

Pressure increasing unit can also be a centrally installed pressure increasing unit, for example, and additionally one on each Filling station arranged pressure reducing unit, in particular be provided in a controllable pressure reducing valve. The problem here is that at low flow speeds due to the high differential pressures between the product supply pressure in front of the pressure reducing station and in the container behind the pressure reducing station, only small nominal diameters can be released, through which the product squeezes due to the high pressure difference with high flow velocities in the valve seat, in order to then expanded pipeline to flow at an average low speed. This "squeezing" can release the easily soluble gas and foam the liquid and change its composition.

In a further development of this inventive concept, compensators connected in parallel may be provided under certain circumstances, by means of which excessive gas release is prevented.

According to a preferred embodiment of the invention, an overflow valve is provided in the return gas line, via which the return gas is discharged.

Further developments, advantages and possible uses of the invention also result from the following description of exemplary embodiments and the drawing. All of the described and / or illustrated features, alone or in any combination, form the subject matter of the invention, regardless of their summary in the claims or their relationship.

Show it:

Fig. 1 is a schematic representation of a filling station according to a first embodiment of the invention and Fig. 2 is a schematic representation of a filling station according to a second embodiment of the invention.

The filling station 1 shown in FIG. 1 essentially consists of a filling valve 2, to which a liquid, such as beer, in which gases are dissolved is supplied via a supply line 3. A container, in particular a keg 4, is placed on the filling valve 2 and is to be filled with the product liquid.

Provided in the feed line 3 is a booster pump 5 assigned to the individual filling station 1, which is controlled by a frequency converter 6 as a function of the pressure in the line section 8 to the filling valve 2 determined by a pressure sensor 7 and the gas pressure in the keg 4.

A riser pipe 9 is provided in the keg 4, which is connected to a return gas line 10 of the filling valve 2. The return gas line 10 leads to an overflow valve 11, via which access to a return gas outlet 12 is controlled. A bias gas line 13 is also connected to the return gas line 10 and 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 C0 ₂ . In the case of certain liquids, for example stout beer, the biasing gas can also be a composition of several gases, such as C0 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 C0 ₂ (or N ₂ ) in the beer, which is approximately at the product pressure in the line section 8 of the supply line 3 before 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. Here it is taken into account that the beer filled at a temperature of about 3 ° C warms by about 4 ° C in the keg 4, which is usually steamed before filling and is therefore hot at about 100 ° C. The change in saturation pressure caused by this is already taken into account when setting the original preload pressure.

If the filling valve 2 is opened after the biasing gas valve 14 is closed, the pressure is initially constant. After switching on the pump 5, which is approached via a "ramp", the filling speed is slowly increased in order not to cause excessive turbulence. The beer conveyed from the supply line 8 through the annular gap 15 in the filling valve 2 into the keg 4 presses the prestressing gas contained in the keg 4 out of the keg 4 through the riser pipe 9. The bias gas escapes via the overflow valve 11 into the return gas outlet 12.

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

The second embodiment shown in FIG. 2 corresponds essentially to the embodiment according to FIG. 1, so that corresponding elements are designated with the same reference numerals and their detailed description is omitted again.

The essential difference to the first embodiment in the embodiment according to FIG. 2 is that an increased pressure is set in the filling station 20 via a central pressure increasing unit 21 in the supply line 3. Each individual filling station 20 is a pressure reducing valve 22 assigned, which reduces the pressure at the filling valve 2 to the supply pressure desired for the product supply at the filling station 20, which is detected by the pressure sensor 7. When opening the filling valve 2, there should first be a constant pressure between the supply line section 8 and the inside of the container 4 and the differential pressure required for beer delivery should then be set via the pressure reducing valve 22, taking into account the pressure determined in the supply line 8 by the pressure meter 7. However, if there is still an increased pressure in the supply line 8 when the filling valve 2 is opened, this is not critical due to the incompressibility of the liquid in the line section 8.

In order to prevent gas from being released through the valve seat of the pressure reducing valve 22 when the product liquid under high pressure is "squeezed" through the valve seat, compensators (not shown in detail) are provided in parallel with the pressure reducing valve 22. The remaining mode of operation corresponds to that of embodiment 1. Here, too, the differential pressure between product feed line 8 and the preload pressure in keg 4 can be set very quickly by pressure reducing valve 22.

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 C0 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. or the absorption of oxygen from the Biasing gas is avoided and the product quality is significantly improved with lower energy consumption and C0 ₂ emissions.

Reference symbol list:

1 filling station

2 filling valve

3 supply line

4 kegs

5 Booster pump 6 Frequency converter

7 pressure transducers

8 line section

9 riser pipe

10 Return gas line 11 Overflow valve

12 return gas outlet

13 leader line

14 valve

15 annular gap 20 filling station

21 pressure increasing unit

22 pressure reducing valve

Claims

Claims:

1. A method for filling containers (4), in particular kegs, with liquids in which at least one gas is dissolved, the container (4) being preloaded with a biasing gas before filling the liquid, then the container (4) via a Filling valve (2) connected to a feed line (3, 8) is fed to a filling station (1, 20) and liquid and the biasing gas contained in the container (4) is discharged during the filling process, characterized in that the biasing gas in the container (4) only on a partial pressure corresponding to the saturation pressure of one of the gases dissolved in the filled liquid, in particular C0 ₂ or N ₂ , is prestressed, which is below the maximum product pressure present in the feed line (8) upstream of the filling valve (2).

2. The method according to claim 1, characterized in that the product supply to the filling station (1) through the supply line (3) takes place at a pressure which is approximately at or slightly below the prestressing pressure in the container (4).

3. The method according to claim 1, characterized in that the product supply to the filling station (20) through the supply line (3) with a pressure which is higher than the biasing pressure in the container (4).

4. The method according to any one of claims 1 to 3, characterized in that the differential pressure to be applied for filling between the product supply and the interior of the container is applied in a controllable manner for each filling station (1, 20) via a pressure control device (5, 22).

5. The method according to any one of claims 1 to 4, characterized in that the biasing gas provided in the container (4) is pressed out by the inflowing product from the container (4).

6. The method according to any one of claims 1 to 5, characterized in that the biasing pressure in the container (4) is set so that it corresponds approximately to the saturation pressure of the dissolved gas in the filled container (4).

7. Device for carrying out a method according to one of claims 1 to 6 with a filling station (1, 20) with a feed line (3, 8), via the product liquid to be filled into a container (4) provided on the filling station (1, 20) is supplied, and with a return gas line (10) via which bias gas escaping from the container (4) is discharged, characterized in that at the filling station (1, 20) a pressure control device (5, 22) for determining the filling pressure in the supply line (8) the filling station (1, 20) is provided.

8. The device according to claim 7, characterized in that the pressure control device (5, 22) is assigned a pressure sensor (7) for determining the product pressure in the supply line (8) of the filling station (1, 20).

9. The device according to claim 7 or 8, characterized in that the pressure control device is a pressure increasing unit (5).

10. The device according to claim 9, characterized in that the pressure increasing unit is a preferably frequency-controlled pump (5).

11. The device according to claim 7 or 8, characterized in that in the feed line (3) a central pressure increasing unit (21) is provided and each filling station (20) is assigned a pressure reducing unit (22).

12. The apparatus according to claim 11, characterized in that the pressure reducing unit is a preferably adjustable pressure reducing valve (22).

13. The apparatus according to claim 11 or 12, characterized in that compensators are provided in parallel to the pressure reducing unit (22).

14. Device according to one of claims 7 to 13, characterized in that an overflow valve (11) is provided in the return gas line (10), via which the return gas is discharged.