WO2024134409A1

WO2024134409A1 - Steam surface treatment machine and process

Info

Publication number: WO2024134409A1
Application number: PCT/IB2023/062746
Authority: WO
Inventors: Paolo Redaelli
Original assignee: Techno Surface Sas di Bulli Elisabetta & C.
Priority date: 2022-12-20
Filing date: 2023-12-15
Publication date: 2024-06-27

Abstract

It is an object of the invention to provide a machine (10) for steam treatments of surfaces, wherein said machine (10) comprises at least one process tank (50) for containing workpieces to be processed, wherein said tank (50) is provided with at least one ejector coirprising a first channel (22) for inlet of pressurized steam and a second channel (24) for inlet of a working fluid for workpieces to be processed, wherein said first channel (22) and said second channel (24) flow into a venturi (26) terminating in an outlet nozzle (28) wherein a mixture of steam and the working fluid flows from said outlet nozzle (28), and wherein said mixture is directed to the workpieces to change the surface condition of said workpieces, and wherein said machine (10) further comprises an aspirator (80) associated with air heating means and which draws air from the outside and sends hot air into the tank (50) by means of a pipe (80').

Description

"STEAM SURFACE TREATMENT MACHINE AND PROCESS" .

FIELD OF THE INVENTION

The present invention relates to a machine for steam treatment of surfaces and a related process .

In particular, the present invention relates to a machine capable of treating the surface of workpieces by subj ecting them to jets of steam in order to clean them, colour them and/or carry out smoothing and roughness mitigation processes on them.

PRIOR ART

Several techniques are known for the treatment of workpieces subjected to finishing processes, which are briefly described here to explain the context of the present invention.

A first known technique is the sandblasting of workpieces, a technique that in turn can be divided into the following categories : depression dry sandblasting, pressure dry sandblasting, wet sandblasting, cryogenic sandblasting and waterjet sandblasting.

In dry depression sandblasting, in an enclosed cabin, the Venturi principle is used to generate a depression within the cabin itself, collect abrasive from a holding hopper and feed it back to a gun or nozzle, until the reduction in size of the used granules is automatically detected as dust .

Metal grit cannot be used with depression sandblasting.

In dry pressure sandblasting, on the other hand, a tank is pressurized by means of pneumatic connections and when the abrasive is recalled, activated for example by a foot pedal on the machine, the contents of a cylinder are discharged through the nozzle .

With pressure sandblasting, the power is about 5 times that of vacuum sandblasting.

Both depression and pressure sandblasting techniques make use of compressed air (i . e . an upstream compressor) to blast sand (or other types of grit such as glass beads, etc. ) .

Limitations of these techniques are as follows .

In addition to medium-high pressures for depression technology and high pressures for pressure technology, consumption expressed in liters of air/hour is high or very high for depression or pressure respectively. Compressed air systems with rather high purchase, operating and maintenance costs are therefore required.

Another well-known technique is wet sandblasting (also called wet sandblast, or improperly vapor sandblast) .

This technique, which is largely similar to dry depression sandblasting, additionally uses a pump to help the mass of abrasive and water reach the gun where it is blasted onto the surface to be sandblasted with a jet of compressed air.

A further well-known technique is ' cryo-blasting' , also known as ' Dry Ice Blasting' , which consists of projecting small pellets of ' Dry Ice ' (or carbonic ice) at a temperature of -78.5°C onto the surface to be treated at sonic or supersonic speed.

By virtue of cryogenic blasting, combined mechanical and thermal effects due to low temperatures are particularly effective in many applications and industries for environmentally friendly cleaning.

By connecting the machine to the utilities required for its operation and loading it with dry ice pellets, cleaning is very easy thanks to the gun and nozzles that allow even the least accessible spaces to be reached .

Carbon dioxide ice is known as ' dry' because under standard pressure conditions, carbon dioxide passes from the solid to the gaseous state by sublimation, namely without passing through the liquid state .

The term carbonic ice or dry ice refers to carbon dioxide (chemical formula: CO2 ) in a solid state, which is obtained when the temperature reaches -78.5 °C (at atmospheric pressure) . It has numerous applications, especially in the medical field and cold storage .

Unfortunately, the storage time for dry ice is about three days under optimal conditions with appropriate insulating containers . Transport costs are expensive as the insulating containers must also be returned each time. The required compressed air of 7 to 14 bar is the major limitation, which results in the use of very expensive compressors .

The eventual purchase of a dry ice pellet production plant is obviously very expensive . The whole, therefore, is not among the most cost- effective of the available techniques .

Another well-known technique is hydro et blasting, which involves a dual operation: dry blasting or low-pressure atomized hydro jet blasting with mixing of water and inert . The mixing of water takes place directly in the nozzle, a method that minimizes the amount of water used and therefore cleaning residues and on site costs . The use of water guarantees total dust abatement, ideal for work in urban environments or where it is particularly important to reduce emissions . The waterjet blasting method is versatile and can be used in restoration, but also in urban decoration, graffiti removal and industrial cleaning. For this technique, chilled and dehumidified compressed air pressure can be adjusted from 0.2 bar and the compressed air/inert air/spray water mixture is micrometrically regulated.

A vibrating sandblasting machine is known from Italian patent application No . 102019000007052.

WO 2005/090002 describes a method for the painting of small parts, whereby small parts are circulated in a machine in a region traversed by a jet from a paint gun. The parts are moved by means of a complex inclined conveyor belt . Specifically, the parts are poured onto the belt, which has perforations through which air is sucked in.

Document CH 400 911 illustrates a classic blasting gun, in which a pressurized fluid arrives at an inlet of a gun tube and flows at very high speed. This flow of fluid through the nozzle of the gun creates a vacuum in the tube and sucks in the material to be sprayed through a side inlet . The fluid thus sucked flows into the pipe, where it undergoes increasing acceleration and is discharged into the nozzle, where it comes into contact with the fluid, which carries it and pushes it towards the outlet .

Document DE 20 2005 020 769 illustrates a mobile vessel such as a rotary tumbler or rototumbler operating on small articles and a spray gun that sprays the coating material towards the small articles in the mobile vessel . An IR radiation device emits radiation into the mobile vessel to dry or harden the coating material by precipitation.

The purpose of the present invention is to realize a machine for surface treatment of workpieces that overcomes the problems of the prior art .

In particular, one purpose of the present invention is to realize a machine that allows workpieces to be dyed in a practical and economical way.

BRIEF DESCRIPTION OF THE INVENTION

Said purposes are achieved by a machine for steam dyeing of surfaces, wherein said machine comprises at least one process tank for holding workpieces to be processed in conjunction with vibratory finishing media, and configured to impose a rotational motion on the workpieces so that they expose their surfaces in the different directions of the space, and wherein at least one ejector comprising a first channel for inlet of pressurized steam and a second channel for inlet of a dye for the workpieces to be dyed, wherein the first channel and the second channel flow into a Venturi tube terminating in an outlet nozzle, wherein a mixture of steam and dye exits from said outlet nozzle and wherein said mixture is directed onto the workpieces for dyeing the workpieces wherein the machine further comprises an aspirator associated with air heating means and which draws air from the outside and sends hot air into the tank by means of a pipe .

An advantage of the invention is that it allows a series of elements to interact in such a way as to dye workpieces with significant dye savings . In particular, the process tank gives the workpieces and vibratory media a rotational motion that exposes their surfaces in all directions of space, while the immersion in vibratory media protects the workpieces during their three-dimensional revolution due to the elasticity of said media, to which it must be added the use of steam as a carrier for the ink or dye .

The invention also relates to a process for steam dyeing the surfaces of workpieces placed in a process tank configured in circular or toroidal form, wherein the said process comprises at least the following steps :

- impose a rotational motion on the workpieces so that they expose their surfaces in different directions in space;

-impose on workpieces a contact action within the process tank with vibratory finishing media;

- employing a dye mixed with dry saturated steam to create a mixture to be ejected against the surfaces of the workpieces placed inside the process tank to colour the workpieces, wherein said phases are preceded by a pre-treatment phase of the workpieces placed inside the process tank wherein said workpieces are treated with dry saturated steam and/or hot air and are followed by a hot water rinse phase by connection of the machine to a hot water line or by implementation of a water heating device installed on board the machine, and wherein the rinsing function can be used, depending on the programmed recipes, only with hot water or in combination with dry saturated steam and/or hot air.

Further features of the invention can be deduced from the dependent claims .

BRIEF DESCRIPTION OF THE FIGURES Further features and advantages of the invention will become apparent from reading the following description provided by way of non limitative example, with the aid of the illustrations in the accompanying tables, wherein

- Figure 1 is a side view of the machine according to an embodiment of the invention;

- Figure 2 is a further side view of the machine according to an embodiment of the invention;

- Figure 3 is an axonometric view of the machine according to an embodiment of the invention;

- Figure 4 is a top view of an ejector belonging to the machine of the invention; and

- Figure 5 is a cross-sectional view along the A-A plane of the figure 4 e ector.

DETAILED DESCRIPTION OF THE FIGURES

The present invention will now be described with particular reference to the attached figures .

The surface steam dyeing machine of the invention is depicted in Figures 1-3 and is globally indicated by the numerical reference 10.

As is well known, dyeing is a process in which the colour penetrates the material, unlike painting, which involves applying a coating, such as paint, to the surface of a material .

In particular, the machine 10 is mounted on a plinth 12 and has a process tank 50, mounted on springs 55, which process tank 50 is made to vibrate by a motor (not shown for simplicity) . In certain processes, vibro finishing media or other fine particles may also be present inside the tank 50 to exert a finishing action on the workpieces in conjunction with the vibration of tank 50.

Machine 10 has a first in-line vacuum generator or ejector 20 for steam dyeing and a second ejector 30 to carry out a possible preheating phase for workpieces to be processed with steam only.

The second ejector 30 can also be used to treat workpieces with steam and abrasive, particularly useful for polymer parts where heat contributes to reducing surface mechanical strength.

This second ejector 30 can also be used to clean tank 50 and vibro finishing media at the end of the cycle .

Figure 4 is a top view of an ejector 20 belonging to the machine of the invention and Figure 5 is a sectional view along the A-A plane of the ejector 20 in Figure 4.

The ejector 20 provides a first channel 22 for the inlet of pressurized steam and a second channel 24 for the inlet of a working fluid for workpieces .

The first channel 22 and the second channel 24 both flow into a venturi 26 that terminates in an outlet nozzle 28.

The pressurized steam, which acts as the driving product, and the working fluid, which can also be referred to as the driven product, mix in a venturi 26 and are directed towards the workpieces, exiting through a nozzle 28.

In an embodiment of the invention, the working fluid is a colouring liquid and, as further illustrated below, the machine of the invention is used to colour workpieces .

The steam used is preferably dry saturated steam at relatively high pressures but low flow rates, e. g. 1.25 1/h per KW used.

More generally, the treated product can be : a) Dyeing liquid for dyeing polymers, fabrics or other materials (but may also be non-liquid, so a gel or granular powders, or emulsions, or other physical states) b) Abrasive gel c) Slurry, or a combination of liquids and solid substances in granules, granular abrasives d) Liquid non-abrasive chemical substance or compound e) Non-abrasive chemical substance or compound in gel form.

At the outlet nozzle 28, the mixture generated by the treatment steam and the treated product is obtained.

Various discharge modes are provided for the fluids contained in the process tank.

Discharge takes place via the automatic, pneumatically controlled discharge valve 42 outside the machine, where a linear actuator directs the discharged effluent to three different destinations .

The discharge into an interchangeable tank 40, such as a bucket or bottle aimed at ink recovery.

Discharge into recycling tank 44, for subsequent re-use one or more times, as appropriate, e. g. for re-use of water/detergent solution (tank with booster pump) .

Discharge into waste water storage or recovery tank 46, for waste water intended for disposal .

According to an embodiment of the invention, the steam dyeing of pieces can be compared to the classic process of immersion dyeing in hot water with dye in solution.

COMPARISON EXAMPLE ACCORDING TO THE PRIOR ART

A classic application example, relating to a well-known hot water immersion dyeing process with dye in solution, is as follows . a. Consider a medium-small heated stainless steel tank (e .g. an ultrasonic cleaning tank) in which to immerse a workpiece at 80 °C for 2 minutes, i . e . a tank with a capacity of 30 liters; b. Consider that the percentage of dye to achieve a result is 1 to 9 - therefore 1 part of (rather expensive) dye for every 9 parts of water is needed, so 3 liters of dye in the tank with 27 liters of water. c. Once the temperature of 80 °C has been reached, the workpieces to be immersed must be allowed to soak for a time of 2 minutes, then removed, rinsed and drained.

The liquid with the colour can be reused for a few times .

EXAMPLE 1

Consider now an application example in which the system of the invention is used, in which there is a steam jet suitably additized with dye, such that a component or workpiece is involved in a three-dimensional manner over its entire surface .

It will be seen that the process of the invention achieves the desired result with less use of dye .

In the process of the invention, a vibration tank 50 (toroidal or circular type) is preferably used.

Inside the vibratory tank 50, the workpieces to be processed (alone or aided by special light elastic inserts or vibro finishing media) are placed in rotation, or in any case in motion according to a rotational motion so that they expose their surfaces in the different directions of space and, as the first step of the process, are brought to a temperature of 80°C by ejector 30.

This occurs while the workpieces pass several times under the jet of dry saturated steam generated by the thermal unit 70.

Once the optimum temperature is reached, the inline vacuum generator 20 kicks in (while the previous ejector jet 30 cuts out) and this results in the supply of dye-added steam, by sucking the ink contained in the container 40 along a 40 ' conveyor line or tube (or via another container and optional precision pump) .

Specifically, the dry saturated steam generated by the thermal unit 70 is conveyed to the in-line vacuum generator 20 via a 20 ' conveyor line, while the dry saturated steam 70 is conveyed to the ejector 30 via a 30 ' conveyor line .

Since the steam flow rate is 4 1/h and the feed ratio is approximately 2/10, this means that in a maximum of 60 minutes, the additive dye can be 41/10 x 2 = 0.8 liters .

However, as the time required for colouring could vary between the same time as in the classic immersion phase to double that time, we will obtain that instead of 2 minutes, 3 to 4 minutes will be required, with a consumption of e . g. 0.8/60 x 4 = 0.0533 liters (the condensed liquid in the tank can be drained and recovered) .

It is concluded that, in order to obtain the dyeing of more or less the same quantity of workpieces, the system of the invention, compared to the classical one, uses 0.1 liter of dye instead of 3 liters, i . e. a ratio of about 30 times less .

Even if this ratio were to vary, it can be statistically stated that the system of the invention offers the possibility of reducing dye consumption in a dyeing process by at least 10 times compared to conventional methods .

It cannot be ruled out that, at the end of several steam dyeing cycles according to the invention, before carrying out a colour change, for example, the use of the ejector 30, this time fed not only with steam from the same generator, but also with abrasive gel or slurry (water/ abrasive mixture) via the peristaltic pump 73, is extremely useful to carry out the cleaning of the tank and of any elastic media (or vibro finishing media) contained therein.

This automatic cleaning process results in an effective environment that, following a simple rinsing (by recycling, via the tank with pump 44 - or with water from the flowmeter with solenoid valve 71, or with the addition of liquid chemical compound via solenoid pump 72) , is ready to receive new articles to be coloured, with a new dye or colour.

Specifically, the abrasive gel or slurry (water/ abrasive mixture) is fed through the peristaltic pump 73 to the ej ector 30 via the 73 ' conveyor line .

In addition, the water coming from the flowmeter with solenoid valve 71 is conveyed to the process tank 50 via a conveyor line 71 ' , while the liquid chemical compound sent to the process tank 50 via solenoid pump 72 is conveyed via a conveyor line 72 ' .

A first possibility of the invention is to use a vibrating process tank 50 mounted on springs 55, which is made to vibrate by a motor, as in Figures 1-3 .

In such a tank 50, the workpieces rotate three-dimensionally inside a toroidal tank and are exposed, in several passes, to the steam-activated blasting jet, via ejector 30, allowing them to be texturized and exposed on each side as they are exposed until 100% surface involvement is achieved.

In this operating dynamic, it is also possible to work with low volumes of parts to be steam-blasted, thanks to the appropriate use of vector media - elastic or non-elastic preforms - capable of performing the dual function of three-dimensional orientation of the workpieces and, on the other hand, avoiding or containing shocks .

According to this same principle, the workpieces subjected to the steam jet are gradually involved in each side of the surface, thus determining, depending on the type of steam jet and principle that is activated in the machine :

According to the steam jet principle, the workpieces are sandblasted or cleaned/ fine-abraded, involved or treated with dry saturated steam, suitably additized with i . Abrasive gel ii . Slurry, or a combination of liquids and solid substances in granules, granular abrasives iii . Liquid non- abrasive chemical substance or compound (e .g. detergent) iv. Non- abrasive chemical substance or compound in a gel (e . g. deoxidant) .

According to the previously described principle of steam dyeing, the workpieces are either dyed or treated with dry saturated steam, suitably additized with dye, via ejector 20 instead of ejector 30, until the desired dyeing of the surface is achieved.

According to an embodiment of the invention, wherein the step of changing the surface condition of workpieces comprises a step of steam dyeing the workpieces in which the dyeing ink is divided into two components .

That is, a first solvent component in the liquid state and a second pigment component, where this second component is realized in the solid state in tablet form.

In the process of the invention, the pigment tablet is loaded with the workpieces to be dyed in the process tank 50 and the solvent is applied by steam to the workpieces in the process tank 50 after a heating step of the surfaces of said workpieces .

An advantage of this solution is that it reduces the volume of flammable liquid and the risk of fire, allowing solid pigments to be stored safely. Alternatively, instead of the vibratory tank 50, a different dynamic can be used for the workpieces, i .e . one that refers to the use of a rotating tumbler instead of a circular vibro- finishing machine .

Such a system achieves similar results by proposing similar movements of the mass with respect to the points where steam, steam and colour or steam and gel are introduced.

A further embodiment of the invention involves its use in rectangular or linear vibratory finishing machines, with which, suitably configured, similar results can be achieved.

A further variant of the invention provides an operating principle according to which it is possible, as an alternative to the other dynamics already described:

Using a controlled axis system (CNC) to orientate each individual workpiece, group or cluster of workpieces or frame with several workpieces, directing them towards a fixed point at which the steam jet exit point is active, thus determining, depending on the type of steam jet and principle that is activated in the machine :

According to the same principles as above, the components are either sandblasted or treated with dry saturated steam, suitably additized with: a. Abrasive gel b. Slurry, or a combination of liquids and solid substances in granules, granular abrasives c. Liquid (or gel) dye for dyeing polymers, fabrics or other materials d. Liquid non- abrasive chemical substance or compound e . Non- abrasive chemical substance or compound in gel form.

Alternatively, orientate the steam jet ejector with a controlled axis system (CNC) towards each individual workpiece, group or cluster of workpieces or frame with several workpieces suitably clamped together, so that all the required surfaces are involved with the steam jet, thus determining, depending on the type of steam jet and principle that is activated in the machine :

A further variant of the invention envisages the operating principle according to which it is possible and/or preferable as an alternative to the other described dynamics :

Using a ROBOT (Scara or anthropomorphic) or COBOT, orientate each individual component, group or cluster of components or frame with several components, directing them towards a fixed point at which the steam jet exit point is active, thus determining, depending on the type of steam jet and principle that is activated in the machine :

According to the same principles as above, the components are either sandblasted or treated with dry saturated steam, suitably additized with: a. Abrasive gel b. Slurry, or a combination of liquids and solid substances in granules, granular abrasives c. Liquid (or gel) dye for dyeing polymers, fabrics or other materials d. Liquid non- abrasive chemical substance or compound e . Non- abrasive chemical substance or compound in gel form

Alternatively, use a ROBOT (Scara or anthropomorphic) or COBOT to direct the steam jet ejector towards a single component, group or cluster of components or a frame with several suitably fixed components, so that all the required surfaces are involved with the steam jet, thus determining, depending on the type of steam jet and principle that is activated in the machine :

Notwithstanding the foregoing, in certain embodiments of the invention, it is possible to benefit the end-user by providing further opportunities to use the same machine for the following additional surface treatment processes .

A first example of these further processes is the lubrication of elastomers, polymers and plastics in general .

This process makes it possible to use the machine to apply liquid or gel chemical compounds in order to apply a lubricating layer to the surface, i .e . coating the surface with a lubricating substance (typical example :

Teflon) . The ability of dry saturated steam to open the porosity of surfaces allows, when used, this process to be more efficient than simply applying identical or similar substances with an airbrush.

A further surface treatment process is waxing or paraffinizing, of natural materials such as corozo, horn, wood, this process allows the machine to apply a protective layer to the surface, i . e. coating the surface (Coating) with a waxy substance (typical example: paraffin or beeswax) .

The application of functional coatings (Functional Coatings) or NanoAdditives (Nano-Coatings) of metals, plastics, glass, polymers, composites, natural materials - these processes, variously identifiable as ' Coatings ' or ' Top-Coatings ' allow the machine to be used to apply a protective or functional layer to the surfaces involved, with high degrees of efficiency.

Note that some nano-additives enable important properties to be achieved. In fact, just as an example, the surface properties of organic polymer coatings can be improved with certain nano-additives to be more hydrophobic, oil-repellent and scratch-resistant .

Additives or Nano-Additives contain nanoparticles created by the hydrolysis and condensation of silanes (sol-gel technology) .

The combination of different silanes, which are synthesized in a special process, results in organically modified silica sols with approximately 30 per cent solids and long life.

A further aspect of the invention may include a heating phase by insufflation of hot air. This can be realized, for example, by means of an extractor fan or blower 80 that draws in air from outside and sends it into tank 50, after heating, using an 80 ' pipe.

This function of heating by hot air insufflation, together with or separate from dry saturated steam, can contribute both to the preliminary pre-heating phase of the components (before applying a dye, lubrication or nano-coating to the surface) and to the final drying phase .

As far as possible modifications and/or improvements to the treatment tank 50 are concerned, a morphological adaptation of the tank bottom is envisaged, aimed at having the lower level of the working tank or vibro finishing tank positioned a few millimeters above the liquid/ waste discharge filter, thus ensuring perfect drying at the end of the cycle with the expulsion/discharge of all the waste water down to the last drop.

A further feature is hot water rinsing - either by connecting the machine to a hot water line (where centralized for several machines) or by implementing (optional) an on-board water heating device; this rinsing function can be used, depending on the programmed recipes :

- Alone (hot water only)

- Combined with dry saturated steam

In some versions, or as an option or addition to the basic machine, an additional function can be provided to apply substances of various natures and bases (aqueous or solvent or nano-technological) to the surfaces involved in the process, by means of an airbrush or painting nozzle associated with a special pump. This optional accessory, when required, allows the machine to be used to apply substances that, due to their nature, are not compatible with the steam venturi mode .

In parallel, it allows additives to be applied via the steam venturi mode described above .

Obviously, modifications or improvements may be made to the invention as described, dictated by contingent or particular motives, without going beyond the scope of the invention.

Claims

CIAIMS

1. Machine (10) for steam dyeing of surfaces, wherein said machine (10) comprises at least one process tank (50) for holding workpieces to be processed in conjunction with vibratory finishing media, and configured to impose a rotational motion on the workpieces so that they expose their surfaces in the different directions of the space, and wherein at least one ejector comprising a first channel (22) for inlet of pressurized steam and a second channel (24) for inlet of a dye for the workpieces to be dyed, wherein the first channel (22) and the second channel (24) flow into a Venturi tube (26) terminating in an outlet nozzle (28) , wherein a mixture of steam and dye exits from said outlet nozzle (28) and wherein said mixture is directed onto the workpieces for dyeing the workpieces wherein the machine (10) further comprises an aspirator (80) associated with air heating means and which draws air from the outside and sends hot air into the tank (50) by means of a pipe (80 ’ ) .

2. Machine (10) as in claim 1, wherein the second channel (24) may be used for a working fluid chosen from a dyeing liquid for dyeing polymers, or for dyeing textiles or for abrasive gels, slurries, or for a combination of liquids and solid substances in granules, granular abrasives, non- abrasive liquid chemical compounds or non- abrasive gel chemical compounds .

3. Machine (10) as at claim 1, in which the second channel (24) can be used for lubrication of elastomers, polymers and plastics in general .

4 . Machine (10) as at claim 1, in which the second channel (24) can be used for waxing or paraffinizing natural materials such as corozo, horn or wood, in order to apply a protective layer made of a waxy substance to their surfaces .

5. Machine (10) as at claim 1, wherein the second channel (24) can be used for applying functional coatings or Nano-Additives, of metals, plastics, glass, polymers, composites, natural materials, or generally coatings to apply a protective layer or functional layer to the surfaces involved, with high degrees of efficiency.

6. Machine (10) as at claim 1, wherein the bottom of the process tank (50) is configured in such a way that the lower level of the process tank (50) is positioned above the liquid or effluent discharge filter, thereby ensuring perfect drying at the end of the work cycle with expulsion or discharge of all liquids or effluents .

7. Machine (10) as at claim 1, wherein the process tank (50) is mounted on springs (55) and is made to vibrate by a motor and is configured in a circular or toroidal form and the workpieces are inside it, or the tank (50) is in the form of a rotating tumbler or is a rectangular or linear vibratory finishing tank.

8. Machine (10) as in claim 1, wherein a controlled axis system (CNC) , or a ROBOT (Scara or anthropomorphic) or a COBOT is provided for orienting each individual workpiece, group or cluster of workpieces or frame with several workpieces directing them towards a fixed point at which the steam jet outlet is active, or to direct the steam jet ejector, towards each individual workpiece, group or cluster of workpieces or frame with several workpieces suitably fixed.

9. Machine (10) as in claim 1, wherein an additional function of applying to the surfaces involved in the process, aqueous or solvent or nano-technological substances, by means of an additional spray gun or painting nozzle associated with a special pump is provided.

10. Process for the steam dyeing of workpiece surfaces in a process tank (50) configured in circular or toroidal form, wherein the process coirprises at least the following steps

-impose on workpieces a contact action within the process tank (50) with vibratory finishing media;

- employing a dye mixed with dry saturated steam to create a mixture to be ejected against the surfaces of the workpieces placed inside the process tank (50) to colour the workpieces, wherein said phases are preceded by a pre-treatment phase of the workpieces placed inside the process tank (50) wherein said workpieces are treated with dry saturated steam and/or hot air and are followed by a hot water rinse phase by connection of the machine (10) to a hot water line or by implementation of a water heating device installed on board the machine, and wherein the rinsing function can be used, depending on the programmed recipes, only with hot water or in combination with dry saturated steam and/or hot air.

11. A process as claimed in claim 10, wherein the step of changing the surface condition of the workpieces comprises a step of steam dyeing said workpieces comprising the use of a steam jet suitably additized with dyeing ink and such that the workpieces are impacted in a three- dimensional manner over their entire surface .

12. Process as in claim 10 or 11, wherein the step of changing the surface condition of the workpieces comprises a step of vapor dyeing said workpieces in which the dye ink is divided into two components, namely a solvent component in a liquid state and a pigment component made in a solid state in the form of a tablet, wherein said pigment tablet is loaded with the workpieces to be dyed in the process tank (50) and the solvent is applied by steam to the workpieces in the process tank (50) after a heating step of the surfaces of said workpieces .