Field of the invention The present invention refers to a device for isolating a processing chamber from the external ambient in processes in which the materials to be treated need to be transferred to or from a processing chamber where a particular atmosphere is present and has to be maintained, for the entire process duration, in terms of chemical-physical conditions like pressure and/or composition and where, therefore, the leakage has to be reduced as much as possible, minimising any possible gas or liquid flux to or from said processing chamber.

The above mentioned device comprises a dynamic seal where this term indicates a seal that, according to the present invention, isolates the processing chamber from the external ambient or from another processing chamber adjacent to it, allowing the material under processing to enter or leave the chamber itself in a continuous way.

State of the art In every process, in which the materials to be treated must be transferred, in a continuous way, from normal atmosphere to processing areas where different chemical-physical conditions like temperature, pressure and/or compositions are present, the leakage and the related gaseous or liquid flux caused by the transfer of the material between different zones must be reduced as much as possible, in order to maintain the gas pressure values and/or the chemical-physical conditions required by the process, constant in the processing area. For this purpose, the equipment used must be provided with dynamic seals.

These devices can be of different types depending upon the kind of process that has to be dealt with.

In case the processing chamber is at a pressure above the ambient pressure, a solution normally used is to employ a sealing fluid in the chamber inlet and outlet ducts and throttling means to reduce its leakage (see patent GB853489).

In case the processing chamber is at a pressure below the ambient pressure, then the lock systems displayed in the patent EP0388811 are the most widely used.

The efficiency of both the above mentioned systems and of similar devices is

based on the reduction of the clearances and passage gaps, but this restriction may cause difficulties to the transit of the material to be processed, for example shaped as a tape, that has to pass through these apertures. It is therefore necessary to find a compromise that must be both technically and economically valid.

Numerous are the difficulties that must be faced reducing clearances and passage gaps: - Too small gaps may end up obstructing the material transit, especially in case of very wide tapes or bands, due to the difficulty of keeping the mechanical tolerances constant on the entire width.

- Impurities, even of very small dimensions, such as, for example, dust or fragments of the material to be processed, may penetrate between the material under processing and the walls of the gap, increasing local friction and hindering the transit of the material itself, eventually causing its damage and the process to stop.

- As the passage gaps extend for the entire width of the manufactured good, and considering the presence of local tensions and forces in the frames and in the guide elements, it is difficult to reach the required precision level on the mechanical tolerances. In addition, said local forces and tensions vary according to the process phases and conditions and, therefore, they are even more difficult to control.

Objects of the invention This invention overcomes the problems found in previous solutions, making available a device comprising a dynamic seal that minimize the flux between the processing chamber and the outside areas in equipment and processes in which the materials to be processed must be transferred, in a continuous way, from the outside to a processing area where peculiar chemical-physical conditions are required.

Obviously the same device can be applied also to connect two processing chambers wherein different conditions are present.

The dynamic seals throttling and reducing the fluid flux according to the present invention are provided with cooling systems in order to form, on part of their

surface, a coating of controlled thickness having enough mechanical strength to oppose the fluid flux without being removed or deformed.

Moreover the invention refers to the equipment for continuous processing of manufactured goods comprising the dynamic seals and to the process in which such equipment are used.

Brief description of the drawings : Fig. 100a-Example of processing chamber for vacuum processes with inlet and outlet conduits and dynamic seals according to the present invention.

Fig. 100b-Example of processing chamber for pressure processes with inlet and outlet conduits and dynamic seals according to the present invention.

Fig. 101-Example of dynamic seal element according to the present invention.

Fig. 102-Different embodiment of the dynamic seal element Fig. 103-Different embodiment of the dynamic seal element Fig. 104-Different embodiment of the dynamic seal element Detailed description of the invention The description will refer to a device applicable to all those cases in which the process conditions require an isolated processing chamber.

With reference to Figures 100a, 100b and 101 the manufactured good F, entering the equipment, is guided by systems, or guide rolls 3, that lead it progressively through the dynamic seals A, which reduce the fluid flow linked to the passage of the material to be treated.

An analogous situation occurs during the transit to the exit.

The dynamic seals A are provided with cooling devices 8, made of pipes carrying cooling fluids, or of Peltier effect coolers.

This cooling process causes a layer of strong solid coating 6 to form on the external surfaces of the cooled parts thanks to the condensation of an auxiliary substance introduced in liquid phase or in vapour phase via the injectors 5.

The thickness of such coating 6 reduces the passages through which the manufactured good F is transferred and limits the flow of gases from the external atmosphere to the chamber (or vice-versa), increasing thus the local impedance as needed.

The condensed layers take place only on the cooled areas.

In fact, said areas are thermally insulated, unlike the remaining parts of the equipment, by spacing elements 7, built of material with low thermal conductivity, whereas the equipment parts adjacent to the above mentioned spacing elements can be heated by heating elements 9, consisting of pipes carrying heating fluids or of electric resistors.

According to a preferred embodiment of the invention, as depicted in Figure 102, the dynamic seal element consists of a slot, whose section has a shape similar to the section of the manufactured good to be treated and slightly larger dimensions.

Figs. 100a, 100b and 101 and the relative descriptions and explanations apply to this example as well.

The high impedance of the dynamic seals is obtained by reducing to the minimum the gap between the materials and the slot walls. An appropriate auxiliary material, in liquid or vapour phase, is injected via the injector 5, in order to be condensed or solidified on the walls cooled by the cooling elements 8.

If, for example, liquid water or steam is injected, the slot inner walls, cooled, in this case, to a temperature below 0°C, will be covered with ice and the ice thickness will reduce the gap existing initially between the slot inner walls and the manufactured good.

The injection of the above auxiliary material will be done in different ways depending upon the pressure inside the processing chamber. In case of vacuum processes, steam can be directly injected on the selected surfaces, in case of pressurised processes, it might be possible, in some cases, to use gaseous or liquid fluids (e. g. steam or liquid water) coming from the processing area.

In the following descriptions it is assumed that the auxiliary fluid is water or steam and consequently the solid coating is made of ice and the start temperature of the making of the coating is 0° Celsius.

The temperature all along the ice coating thickness is below 0° Celsius. An increase in the cooling effect causes the ice thickness to grow and the distance between the ice surface and the material under processing decreases. The thermal transmission between the ice and the material under processing (generally at ambient temperature) accordingly increases.

The increased transmission of heat, if the temperature of the part on which the ice

layer has formed remains constant, causes an increase in the surface temperature of the ice layer facing the tape of material under processing, until said temperature reaches 0°C and, at this point, the growth of the ice layer stops.

In case the material F accidentally gets in contact with the ice layer, the latter will tend to melt locally in correspondence to the contact area and the friction between the moving tape of material under processing and the ice layer is normally so small that no harmful effect is produced.

It is possible to reduce the residual gap between the ice and the material and even to eliminate it, by reducing the temperature of the part on which the ice has formed. When the residual gap is eliminated, the tape of material under processing gets in contact with the ice layer and scrubs it, thus causing a friction that, although small, causes a braking action on the motion of the manufactured good; this action can be easily picked up and measured by the traction systems of the manufactured good, which are currently used on continuous process equipment.

If the braking action exceeds the pre-set values, it is sufficient to increase the temperature of the part on which the ice layer has condensed, acting on elements 8, to bring the system back to the desired conditions.

In order to limit cooling only to the areas where a layer of condensed material-for example ice-is needed, said areas are separated from the other parts of the equipment, by spacing elements 7, made of material with low thermal conductivity which limit the thermal flow to adjacent parts and the latter may be heated by elements 9, if necessary.

As it is shown in Fig. 102 said cooling elements can be placed in a direction orthogonal to the running direction of the manufactured good F (Fig. 102a), or in a parallel direction (Fig. 102b).

The dynamic seals according to the invention can be applied, for example, to processes including vacuum treatments, thermal treatments, chemical or plasma treatments, application of thin layers of material by means of physical and chemical evaporation, sputtering, etc. , onto manufactured goods such as metallic tapes, structural shapes, threads, yarns, fabrics, rolled sections, plastic films, extruded objects, etc. , even remarkably long ones.

The dynamic seals according to the invention can be applied also to pressurised processes like dyeing, bleaching, cleaning, washing, steaming and others particularly for textile materials.

It can also be placed, from a point of view of applications, in the field of construction of equipment and devices for these processes.

In view of the above said the arrangement and set-up of the heating and cooling elements can be obviously adapted to the specific application for which they are foreseen; some examples of different arrangements are described hereinafter.

In the embodiment depicted in Fig. 103, the dynamic seal element is obtained by means of elements 11, which are movable and couple with guiding and supporting rolls 10; the adjustable elements are cooled and a solid layers of auxiliary material, for example ice, is formed on them thus reducing existing gaps, while the guide rolls 10 can be heated.

In such version the rolls 10, besides guiding the manufactured good F, manage to reduce the gaseous flow. <BR> <BR> <P>In this case the solidified coat, e. g. , ice, builds both between guide rolls and adjustable elements, and between the latter and the thermal spacer 7.

In the preferred embodiment depicted in Fig. 104, the dynamic seal element is obtained by coupling a roll 12, to which the material to be processed is delivered via guide rolls 3, with a cooled cavity.

In such a solution, the roll 12 is heated to compensate for the thermal losses due to the vicinity of the cooled cavity and the material under processing lies throughout its passage inside the dynamic seal element, on roll 12, which permits correct conveyance of the material itself. The friction effects, due to accidental or intentional contact between the tape of material and the layer of condensed material, for example ice, are normally very light and they don't disturb its correct flow.

In this version it is consequently possible to increase the thickness of the layer of material applied inside the cylindrical cavity, for example ice, until the entire gap between the cavity and the manufactured good or between the cavity and the roll 12 is completely filled. Thus, a very high impedance is produced and, to guarantee correct operation, the tension on the tape of material under processing has to be

sufficient and the motor driver of roll 12 has to be powerful enough to overcome the friction effect.

In this case it is not necessary to heat the guide rolls (13), because, while revolving, they are alternately exposed to cold and hot zones.

Among the auxiliary materials used to form the condensation and/or solidification layer, water is certainly the most economical one but, for special needs, also other materials can be used.

The auxiliary material used has to: Be compatible with the manufactured good and the process run in the equipment; adhere to the parts on which it is applied, with such mechanical characteristics as to withstand the pressure excursion to which it is subjected, without being taken off be suitable for being locally injected in a liquid and/or gaseous phase.

The auxiliary material can be introduced by using a normal injection pump, or compatible system, easily available on the market and not shown on the figures due to its obviousness.

To assess and measure the auxiliary material thickness, it is possible to proceed in several ways, choosing systems and sensors widely available on the market as shown in the following non-exhaustive examples : - Proximity sensors and systems that measure the distance between parts of the equipment and the surface of the solid material coating.

- Optical sensors and systems that measure the IR radiation that crossed the supporting area proceeding from an IR source of known characteristics.

- Sensors and systems based on pressure measurement upstream and downstream of the supporting device.

- Torque sensors and systems that measure the resistance to the motion of the tape of material under processing, determined by the friction between the manufactured good and the coating applied on the walls of the supporting area.

On the basis of the above mentioned measurements, it is possible to regulate thickness acting on the cooling system and adjusting the temperature of the cooled parts.

In the technically simples, and also most economical case, in which such auxiliary substance can be water, the supply system may be not necessary as in the two

following cases: Vacuum processes (see patent EP388811) in which, in the gaseous flow coming from the external atmosphere, the quantity of steam that is naturally contained in the air is sufficient for the purposes of this invention. b) Pressure processes (see patent GB853489) in which liquid water or steam is present in the process fluid or in the sealing fluid, they can be used to form the above described condensed or solidified layer, provided that it is not harmful to the material of which the gap walls are made of.

Referring to Fig. 100a, in case of vacuum processes, the vacuum in the processing chamber is made by appropriate pumping systems connected to the duct 4. Depending upon the degree of vacuum requested by the process auxiliary pumping systems might be required and connected to the conduits 2.

In case of pressure processes the mixture of fluids required by the process taking place inside the chamber is introduced through the duct 4 as displayed in Fig.

100b.