Background Art The filling of containers with liquids, such as dairy products, today places high demands on a hygienic environment. Aseptic conditions are required when the products contain bacteria which could multiply and become a health hazard.

The currently used methods for filling containers with liquids are based on the liquid being stored in a main tank. In order to transfer the correct amount of liquid to each container, the liquid is first transferred from the main tank to a number of separate balance tanks.

Then the liquid is transferred from the balance tank to a container. In the balance tank, especially in corners and along edges where the liquid is stagnant, and in connec- tions to and from the tank, bacteria in the liquid tend to grow and multiply, which in turn may cause cultures injurious to health. This means that it is necessary to continuously clean a large number of balance tanks to retain an aseptic environment and to avoid health hazards caused by bacteria in the final product, for instance in milk.

The balance tanks are in many cases equipped with some sort of level monitor which monitors that the cor- rect amount of liquid is transferred from the main tank.

The liquid is transferred between the tanks through con- duits and the flow is controlled by means of valves, in which bacteria cultures can also grow.

Summary of the Invention An object of the present invention is to obviate or reduce the hygienic problems that exist in the current technique when liquid foodstuffs are to be packed.

A further object is to provide a simple device for filling a container with liquid.

These objects are achieved by a method and a device according to claims 1 and 8, respectively.

According to the invention, a flow of liquid is thus controlled in filling by means of a squeezing device, which acts on a deformable tube and which when being returned to a squeezing position is moved countercurrent- ly to produce a subatmospheric pressure in the tube down- stream of the squeezing position.

Such a valve structure obviates stagnant accumula- tions of liquid where bacteria can thrive.

The returning of the squeezing means against the deformable tube comprises the step of producing a back suction in the tube downstream of the squeezing means by moving the squeezing means countercurrently to the squeezing position. When the liquid ceases to flow, the back suction in the tube makes the liquid stay in the lower portion of the tube, thereby preventing dripping.

According to a preferred embodiment, the tube has a self-closing nozzle which is inserted into the container to let the liquid flow into the same. This reduces the risk of liquid spillage during the transfer of liquid to the container. A good fit between the nozzle and the con- tainer prevents liquid from contacting the surroundings.

Preferably, the nozzle is made of an elastically deform- able material. As a result, its self-closing function can be accomplished by designing it in such manner that its outlet opens when a pressure is applied, i. e. by turning on the flow of liquid. Preferably, the cross-sectional opening of the inlet of the nozzle is larger than the cross-sectional opening of the outlet of the nozzle in its fully open state. This results in a pressure above atmospheric in the nozzle. This pressure above atmosphe- ric together with the elastic deformability of the nozzle ensures an additionally improved fit between the nozzle and the container.

The back suction in the tube also causes the aper- ture of the nozzle to close, which prevents the liquid from contacting the surroundings during periods between filling operations.

By an amount of liquid transferred to a container being measured with the aid of a meter, it is possible to control the squeezing action of the squeezing device on the tube and fill the container with a correct amount of liquid.

The need for balance tanks, which have surfaces and edges where bacteria can grow, thus disappears, and it becomes easier to maintain an aseptic environment. When the tube is squeezed, the flow of liquid is prevented, without any edges or surfaces forming where cultures of bacteria can grow. When the flow is once more turned on, there is no area with stagnant liquid left. According to the invention, a device is provided, which in terms of construction can be made considerably simpler than pre- vious constructions including balance tanks.

The deformable tube can, by being subjected to dif- ferent degrees of outer pressure, change the flow of liquid to the container, which makes it possible to reduce the number of valves through which the liquid passes and to facilitate cleaning. The tube is easy to clean and can also readily be replaced when required to maintain a hygienic environment.

The method and the device according to the inven- tion further make it possible to add gaseous additives to the liquid. Up to now, this has been made difficult by great leakage in, inter alia, balance tanks. It is, for instance, desirable to be able to add small amounts of carbon dioxide to milk to improve its keeping quali- ties. With previous filling methods, this has been diffi- cult to achieve at a reasonable cost, since such adding has been associated with considerable spillage of carbon dioxide.

Preferred embodiments of the invention are evident from the dependent claims.

In a preferred embodiment of the invention, the mea- surement of the amount of liquid comprises the steps of beginning the measurement at the same time as the duct opens and terminating the measurement when a predetermin- ed amount has been measured. It is particularly preferred that the duct is closed in response to a predetermined amount being measured. Thus, the transferred amount is accurately controlled.

A preferred method of measuring the transferred amount of liquid to the container comprises the step of measuring the time during which the liquid flows from the tank to the container. The time in which the liquid is allowed to flow through the tube decides how much liquid is transferred to the container. If the pressure of the liquid through the duct is kept essentially constant, a time-based measurement will be very easy and useful.

Another preferred method of measuring the transfer- red amount of liquid to the container comprises the step of measuring by means of a flow meter the flow of liquid through the filling duct and simultaneously calculating the transferred amount.

A third preferred method of measuring the transfer- red amount of liquid to the container comprises the step of weighing of the container together with the amount of liquid that has been transferred to the same.

The step of making the liquid flow into the con- tainer by opening the filling duct comprises advanta- geously the step of supplying of a gas to the flowing liquid when being transferred to the container. A gas supplying device is then arranged in the duct for supply- ing gas directly to the liquid during filling. Supplying a gas in connection with the final filling of the con- tainer results in a reduction of the total amount of con- sumed gas since the losses are considerably smaller than in methods that have been used up to now. The reduced

consumption of gas leads to lower costs and to the fact that new fields of application become realistic.

Brief Description of the Drawings The invention will now be described in more detail with reference to the accompanying drawings which for the purpose of exemplification illustrate a currently prefer- red embodiment.

Fig. 1 is a side view of a filling device with cer- tain parts removed for better clarity.

Fig. 2 is a longitudinal section of the filling device along line II-II in Fig. 1.

Fig. 3 is a sectional view of a nozzle associated with the filling device.

Fig. 4 is a block diagram of the filling device.

Description of a Preferred Embodiment Fig. 1 is a side view, seen in the travelling direc- tion of a web of containers, of a device 100 for filling a container 1 preferably with a liquid. The device will be described below with reference to milk, but is also suited for filling with other liquids and pulverulent substances.

The filling device 100 comprises a frame 40 and a vertically adjustable carrying means 10 arranged there- on and shown in a raised position. Moreover, the filling device 100 comprises a filling duct 15 which is connected to a storage tank (not shown) and which consists of a deformable tube 20 with a filling nozzle 25 at its lower end, and a squeezing means 30 which is arranged round a throttle portion 22 of the tube 20 and which comprises a supporting device 31 arranged at a first side of the tube 20 and a squeezing member 32 arranged at the opposite side of the tube 20. For better clarity, a number of com- ponents of the filling device 100 in Fig. 1 have been omitted.

The supporting device 31 of the squeezing means 30 is fixedly connected to the carrying means 10 and forms a concavely curved squeezing surface 33 facing the tube

20. The squeezing member 32 is circular and suspended from the carrying means 10 in an asymmetrically pivot- able manner. Thus, the squeezing member 32 forms a convex squeezing surface 34 facing the tube 20 and the sup- porting device 31. The squeezing member 32 is pivotable in the manner indicated by the double arrow 35 and thus opens the duct 15 by a combined motion downstream and outwardly away from the tube 20 and closes the duct 15 by a combined motion upstream inwardly towards the tube 20. By closing occurring in a combined squeezing motion and upstream motion, a subatmospheric pressure is gene- rated in the tube 20 downstream of the squeezing means 30, thereby preventing dripping when the duct 15 is closed.

The carrying means 10 which carries the tube 20 and the squeezing means 30 is vertically adjustable in the frame 40 in such manner that the filling nozzle 25 can be inserted into a duct means 16 of a container 1 to begin the filling operation and can be removed from the duct means 16 of the container 1 after filling.

On the frame 40, there is arranged an opening means 50 in the form of two pivotable opening arms 52, at the ends of which suction cups 54 are mounted. The suction cups are connected to a vacuum source. By pivoting, by means of the opening arms 52, the suction cups 54 to the sides of the duct means 16 of the container 1 and then applying a subatmospheric pressure to the suction cups 54 while at the same time the opening arms 52 are pivot- ed slightly outwards, the duct means 16 opens so that the filling nozzle 52 can be inserted into the same, which is effected by moving the carrying means 10 downwards.

Fig. 1 also illustrates a pair of conveying arms 45 which are arranged on rotatable conveying rods 46 which are adapted to reciprocate. When conveying a web 210, as shown in Fig. 2, of containers 1, the conveying arms 45 are pivoted to engage the web 210, whereupon the convey- ing rods 46 perform a striking motion in the travelling

direction of the web 210 to move the web 210. Subsequent- ly, the conveying arms 45 are pivoted away from the web 210 and the conveying rods 46 are returned to the start- ing position to repeat the procedure.

Fig. 2 is a side view of a filling device 100 as shown in Fig. 1. Also in this Figure, some components have been omitted for better clarity. There is shown a chamber 60 which is arranged round the filling nozzle 25 and the duct means 16 of the containers 1 to provide an aseptic filling environment. The compartment 60 comprises a rail 62, in which the duct means 16 is guided, a bel- lows 64 surrounding the filling nozzle 25, and a delivery duct 66 for a sterile gas, such as hot sterile air.

Fig. 2 also illustrates a web 210 of containers 1 of a flexible plastic material, which are conveyed into the filling device 100 in the direction of arrow 3, which is the travelling direction of the web. The containers 1 are collapsible and comprise flexible walls which are inter- connected to form a compartment whose volume depends on the relative position of the walls. The duct means 16 is arranged between two side walls and extends from the com- partment to the outside of the container 1. In position A, a sealed container 1 is shown, the duct means 16 of which is sealed in its outer end portion 18. A cutting device 70 with a motor 74 and a rotary cutting blade 72 which is arranged on each side of the web 210 and of which only one is shown, is mounted in the rail 16 to open the container 1 by cutting off the sealed end por- tion 18 of the duct means 16.

After the cutting device 70, seen in the travelling direction 3, there is a filling station with the filling nozzle 25 of the filling duct 15 and one step further, there is a sealing station 80 (not shown) comprising two hot press jaws 82 to seal the duct means 16 of the filled containers 1.

The rail 62 is elongate and has an essentially ver- tical rectangular cross-section with a slot 63 which is

formed in its underside and in which the duct means 16 is guided. The slot 63 is adjacent to the filling nozzle 25 expanded to an elliptic opening to allow opening of the duct means 16 and insertion of the filling nozzle 25 into the same. Furthermore, the rail 62 comprises adjacent to the filling nozzle 25 a cylindrical connecting portion 68 arranged on its upper side and intended for the bellows 64.

The filling nozzle 25, which is shown in more detail in Figs 2 and 3, has an end portion 26 of elongate cross- section, which in its transverse direction tapers off to an elongate outlet 27 with opposing edge portions 28 which engage each other. The end portion 26 also tapers slightly in the longitudinal direction of the elongate cross-section, as is evident from Fig. 2. The filling nozzle 25 is made of an elastically deformable material, such as an elastic plastic, preferably silicone rubber, and is self-closing, i. e. the edge portions 28 of the outlet 27 engage each other to seal the outlet 27 in the absence of application of outer forces. Such application of outer forces is achieved, for instance, by turning on the flow of liquid, thus enabling the liquid pressure to open the nozzle. The outlet 27 of the nozzle is in its fully open state smaller than the inlet 24 of the nozzle.

This results in a pressure above atmospheric in the nozzle 25, which thus expands and is pressed against the duct means of the container 1. The filling nozzle has at its end facing away from the end portion 26 a connecting portion 29 to be connected to the filling duct 15. A thus designed filling nozzle 25 is particularly suitable to be inserted into the duct means 16 of the container 1 and seal against the inside thereof.

As shown in Fig. 4, the filling device 100 also com- prises a control means 2 which controls the opening and closing of the duct 15 with the squeezing means 30. The control means 2 is also connected to a meter 4 for mea- suring the passing amount of liquid. The control means

2 is adapted to start measuring at the same time as the duct 15 opens and to close the duct 15 in response to a predetermined amount being measured. The meter 4 can, as will be described in more detail below, be designed in one of a plurality of different ways, for instance, for weighing the container 1 during filling, measuring the volume flowing through the duct 15 or measuring the time passing after opening of the duct 15.

In operation of the filling device 100, sterile gas flows into the bellows 64 through the delivery conduit 66 and further into the rail 62. The gas then escapes through the slot 63. The bellows 64 permits a sterile environment at the filling station round the filling nozzle 25 while at the same time the nozzle can be raised and lowered unimpededly. With the chamber 60 it is ensur- ed in an easy and reliable manner that filling occurs in a sterile environment.

When filling an empty and previously sterilised con- tainer 1, it is first inserted into the sterile environ- ment in the rail 62, whereupon the container 1, which at this stage is collapsed and empty, is opened in the cut- ting device 70. The open container 1 is then conveyed to the filling nozzle 25, adjacent to which the opening means 50 expands the duct means 16 and the filling nozzle 25 is moved down and into the same. In this connection, the squeezing means 30 opens and the container 1 is fill- ed with milk, which increases the volume thereof, the meter 4 beginning to measure the amount of liquid sup- plied to the container. When a predetermined amount has been measured, the squeezing means 30 closes in response thereto. In closing, a subatmospheric pressure forms in the tube 20 adjacent to the filling nozzle 25, and there- fore its outlet 27 is sealed. The container 1 is then conveyed further to the sealing station 80 where it is sealed once more.

In a preferred method, the measuring operation is carried out by measuring with the aid of a weighing means

(not shown) on which the container 1 is placed or from which it is suspended during the filling process. When the container reaches a predetermined weight, a signal is given to the control means 2, which in turn controls the squeezing means 30 to closing.

In a further preferred method, the measuring ope- ration is carried out by the volume flowing through the duct 15 being measured by means of a flow meter (not shown) with a calculating unit (not shown) connected thereto and adapted to calculate the passing volume and emit a signal to the control means 2 when the predeter- mined volume has been reached.

In one more preferred embodiment of the invention, the measuring operation is carried out by measuring the time passing from the moment the squeezing means opens.

At a predetermined point of time, a signal is emitted to the control means. In this embodiment, use is made of the fact that the flow through the duct is relatively con- stant when the squeezing means is open. In a particularly preferred embodiment, a weighing means is arranged after the filling station for check weighing. When required, a feed-back coupling is effected in case of deviations from a predetermined volume for any adjustments of the prede- termined time.

In a preferred embodiment of the filling device, a means for supplying carbon dioxide is arranged in the filling duct. It is particularly preferred that this sup- ply means is connected to the control means in such man- ner that the supply occurs directly to the duct only when the duct is open and liquid flows into the container.