Fluid handling – Systems – Multi-way valve unit
Reexamination Certificate
2000-04-11
2001-04-17
Fox, John (Department: 3753)
Fluid handling
Systems
Multi-way valve unit
C137S312000
Reexamination Certificate
active
06216736
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a three-way antimix valve for a pourable food product packaging machine.
BACKGROUND OF THE INVENTION
Machines for packaging pourable food products, such as fruit juice, wine, tomato sauce, pasteurized or long-storage (UHT) milk, etc., are known in which packages are formed from a continuous tube of packaging material defined by a longitudinally sealed strip.
The packaging material has a multilayer structure comprising a layer of paper material covered on both sides with layers of heat-seal material, e.g. polyethylene. In the case of aseptic packages for long-storage products such as UHT milk, the packaging material comprises a layer of barrier material defined, for example, by an aluminium film, which is superimposed on a layer of heat-seal plastic material and is in turn covered with another layer of heat-seal plastic material which eventually defines the inner face of the package contacting the food product.
For producing aseptic packages, the strip of packaging material is unwound off a reel and fed through a sterilizing unit in which it is sterilized, for example, by immersion in a bath of liquid sterilizing agent such as a concentrated solution of hydrogen peroxide and water.
More specifically, the sterilizing unit comprises a bath filled, in use, with the sterilizing agent in which the strip is fed continuously; and an aseptic chamber in which the strip of packaging material issuing from the sterilizing bath is treated to remove any residual sterilizing agent, e.g. by means of drying rollers and jets of high-temperature sterile air.
Before leaving the aseptic chamber, the strip is folded into a cylinder and sealed longitudinally to form in known manner a continuous, vertical, longitudinally sealed tube. The tube of packaging material, in fact, forms an extension of the aseptic chamber and is filled continuously with the pourable product and then fed to a forming and (transverse) sealing unit for forming individual packages and by which the tube is gripped between pairs of jaws to seal the tube transversely and form aseptic pillow packs.
The pillow packs are separated by cutting the sealed portions between the packs, and are then fed to a final folding station where they are folded mechanically into the finished form.
On known machines of the type briefly described above, the tube of packaging material is filled continuously by a conduit forming part of a circuit for supplying the pourable food product for packaging (hereinafter referred to simply as the “product circuit”). The product circuit must be sterilized with aseptic air before the start of each processing cycle, and flushed with a liquid solution at the end of the work cycle; for which purpose, the product circuit must therefore be connected selectively to a flush solution supply circuit and a sterile-air supply circuit by means of a switching assembly for preventing mixing of the various fluids and any traces of the flush solution in the product due to imperfect sealing. For safety reasons and to ensure sterility of the product circuit, the product circuit is normally connected to the switching assembly by means of a service conduit fitted with a two-way, aseptic, e.g. steam-barrier, on-off valve.
Substantially two switching assembly design solutions are known.
A first consists simply in using a movable fitting connected permanently to the service conduit of the product circuit and having connecting means for selective connection to the flush solution and sterile-air supply circuits. Though straightforward and cheap, this solution has the drawback of switching manually from one work stage to the other, by physically disconnecting and reconnecting the movable fitting to the relative circuits.
A second known solution consists in using three three-way valves, each of which has a pair of gates connected to a respective pair of circuits, and a third gate connected to a drain conduit for draining off any leakage from the valve and so preventing undesired leakage caused by pressure on the seals of the other valves.
Though enabling automatic switching, this second solution is expensive and involves considerable load losses.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a three-way antimix valve designed to eliminate the aforementioned drawbacks typically associated with known switching assemblies.
According to the present invention, there is provided a three-way antimix valve for a pourable food product packaging machine, the valve comprising a casing having a lateral wall defining a cavity having an axis of symmetry and communicating with a bottom drain opening; and a rotary shutter rotating about said axis and housed in said cavity with a respective lateral surface cooperating in fluidtight manner with said lateral wall of said casing; said casing having a first gate and a second gate, both formed in said lateral wall and spaced angularly by a first angle, and a third gate formed in said lateral wall in an intermediate position with respect to said first and second gate and spaced angularly with respect to each by a second angle equal to half said first angle; said rotary shutter having a first and a second opening, both formed in said lateral surface and spaced angularly by an angle equal to said second angle, and an inner passage connecting said first and second opening; said lateral wall of said casing having two inner recesses formed respectively between said first gate and said third gate and between said second gate and said third gate; said rotary shutter comprising at least three recesses, of which a first recess is formed between said first and second opening, a second recess is formed on the opposite side of said second opening with respect to said first recess and spaced angularly with respect to the first recess by an angle equal to said second angle, and a third recess is located on the opposite side of said first opening with respect to said first recess and spaced with respect to the first recess by an angle equal to said second angle; said recesses of said casing and said recesses of said rotary shutter communicating with said bottom drain opening of said casing; said valve comprising actuating means for moving said rotary shutter between a first work position in which said first and second opening of said rotary shutter communicate respectively with said first gate and said third gate of said casing, an intermediate position in which said first and second opening of said rotary shutter communicate with respective said recesses of said casing, and said first, second and third gate of said casing communicate with respective recesses of said rotary shutter, and a second work position in which said first and second opening of said rotary shutter communicate respectively with said third gate and said second gate of said casing.
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Burns Doane Swecker & Mathis L.L.P.
Fox John
Tetra Laval Holdings & Finance S.A.
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