Fluent material handling – with receiver or receiver coacting mea – Processes – Filling dispensers
Reexamination Certificate
2000-11-09
2001-10-23
Maust, Timothy L. (Department: 3751)
Fluent material handling, with receiver or receiver coacting mea
Processes
Filling dispensers
C141S083000, C141S114000, C141S115000, C141S192000, C251S009000, C222S571000
Reexamination Certificate
active
06305438
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method of filling a container with a liquid and a filling device therefor.
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 connections 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 correct amount of liquid is transferred from the main tank. The liquid is transferred between the tanks through conduits 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 countercurrently to produce a subatmospheric pressure in the tube downstream of the squeezing position.
Such a valve structure obviates stagnant accumulations 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 container prevents liquid from contacting the surroundings. Preferably, the nozzle is made of an elastically deformable 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 atmospheric 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 aperture 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 previous constructions including balance tanks.
The deformable tube can, by being subjected to different 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 invention 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 qualities. With previous filling methods, this has been difficult 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 these invention, the measurement 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 predetermined 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 transferred 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 transferred 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 container by opening the filling duct comprises advantageously 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 supplying gas directly to the liquid during filling. Supplying a gas in connection with the final filling of the container results in a reduction of the total amount of consumed 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.
REFERENCES:
patent: 4401141 (1983-08-01), Rosen et al.
patent: 4524944 (1985-06-01), Sussman
patent: 5402823 (1995-04-01), Cole
patent: 5458581 (1995-10-01), Hull
patent: A1-4126136 (1993-02-01), None
patent: A1110189 (1984-06-01), None
Derwent's Abstract, No. 93-195008/24, Week 9324 SU 1742131 (Jun. 23, 1992).
Mossberg Ulf
Sjöholm Johan
Birch & Stewart Kolasch & Birch, LLP
Ecolean AB
Maust Timothy L.
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