IT202100016664A1 - MACHINE FOR STEAM TREATMENTS OF SURFACE AND RELATED PROCEDURE - Google Patents

Description

DESCRIPTION

of the Italian Patent for Industrial Invention entitled:

?MACHINE FOR STEAM TREATMENTS OF SURFACE AND RELATED

METHOD?

FIELD OF THE INVENTION

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

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

PRIOR ART NOTE

Many techniques for treating pieces subjected to finishing processes are known which are briefly described herein to clarify the context of the present invention.

A first mode? of the prior art? the sandblasting of the pieces, a technique which in turn can be used? divided into the following categories: vacuum dry blasting, pressure dry blasting, wet blasting, cryogenic blasting and water jet blasting. In vacuum dry sandblasting, in a closed booth, the Venturi principle is exploited to generate a vacuum inside the booth itself, collect the abrasive from a containment hopper and send it back to a gun or dispenser, until the dimensional drop of the used granule is not automatically perceived as powder.

Metallic grits cannot be used with vacuum sandblasting.

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

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

Both vacuum and pressure sandblasting techniques make use of compressed air (therefore an upstream compressor) to perform the function of blasting the sand (or other types of grit such as glass microspheres, etc.).

Limitations of these techniques are as follows.

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

Another known technique? wet sandblasting (also called wet blast, or improperly vapor blast).

This technique, largely similar to that of vacuum dry sandblasting, uses more? a pump to help the mass composed of abrasive and water reach the gun where, with a jet of compressed air, it is projected onto the surface to be sandblasted.

Another known technique? the ?cryo-sandblasting?, also known as ?Dry Ice Blasting?, consists in projecting at speed sonic or supersonic small pellets of ?Dry Ice? (or carbonic ice) at a temperature of -78.5?C on the surface to be treated.

Thanks to cryogenic sandblasting, combined mechanical and thermal effects due to low temperatures are particularly effective in many applications and industrial sectors for cleaning with low environmental impact.

By connecting the machine to the utilities necessary for its operation and loading it with dry ice pellets, cleaning is very simple thanks to the gun and nozzles that allow you to reach even the least accessible spaces.

AND? known that the ice of carbon dioxide is defined as "dry" why? under standard pressure conditions, carbon dioxide passes from the solid to the gaseous state by sublimation, i.e. without passing through the liquid state.

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

Unfortunately, dry ice storage times are approximately three days in optimal conditions with special insulating containers. Transport costs are expensive as the insulating containers must also be returned every time. The required compressed air, from 7 to 14 Bar? the major limitation, which determines the use of very expensive compressors. The eventual purchase of a dry ice pellet production plant is evidently very expensive. The set, therefore, not ? among the most convenient among the available techniques.

Another known technique? water jet sandblasting, which has a dual function: dry or with a low pressure nebulised water jet with mixing of water and inert materials. The mixing of the water takes place directly in the nozzle, mode? that allows you to minimize the amount? of water used and therefore cleaning residues and construction site costs. The use of water guarantees total elimination of dust, ideal for working in urban environments or where it is particularly important to reduce emissions. The water jet sandblasting method? versatile, usable in the context of restoration, but also of urban decoration, in the removal of graffiti and in industrial cleaning. This technique requires an adjustable pressure of refrigerated and dehumidified compressed air starting from 0.2 bar and a micrometric adjustment of the compressed air/aggregate/vaporised water mixture.

A vibratory sandblasting machine? known from Italian patent application No. 102019000007052.

Purpose of the present invention? that of realizing a machine for treating the surfaces of workpieces which allows the problems of the prior art to be overcome.

In particular, an object of the present invention ? that of realizing a machine that allows to color workpieces in a practical and economic way.

BRIEF DESCRIPTION OF THE INVENTION

Said objects are achieved thanks to a machine for steam treatment of surfaces, where the aforementioned machine comprises at least one tank for containing the pieces to be processed, where the aforementioned tank ? at least one ejector has been applied comprising a first channel for the entry of pressurized steam and a second channel for the entry of a working fluid for the pieces to be processed, where the first channel and the second channel flow into a Venturi ending with an outlet nozzle, where a mixture of steam and the working fluid comes out of the aforementioned outlet nozzle and where this mixture is directed on the workpieces to change the state of the surfaces of the aforementioned workpieces.

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

BRIEF DESCRIPTION OF THE FIGURES

Further characteristics and advantages of the invention will become apparent from reading the following description provided by way of non-limiting example, with the aid of the figures illustrated in the attached tables, in which:

- figure 1 ? a side view of the machine according to an embodiment of the invention;

- figure 2 ? a further side view of the machine according to an embodiment of the invention;

- figure 3 ? an isometric view of the machine according to an embodiment of the invention;

- figure 4 ? a top view of an ejector belonging to the machine of the invention; And

- figure 5 ? a sectional view along the plane A-A of Figure 4 of the ejector.

DETAILED DESCRIPTION OF THE FIGURES

This invention will come now described with particular reference to the accompanying figures.

The machine for steam treatment of surfaces of the invention ? depicted in figures 1-3 and ? globally indicated with the reference number 10.

In particular, the car 10 ? mounted on a base 12 and ? provided with a process tank 50, mounted on springs 51, which process tank 50 ? made to vibrate by a motor (not represented for simplicity?).

In certain processes, vibrofinishing media or other fine particles may also be present inside the tank 50, suitable for exerting a finishing action on the workpieces together with the vibration of the tank 50.

The machine 10 has a first in-line vacuum generator or ejector 20 for steam dyeing and a second ejector 30 for carrying out a possible preheating phase of the pieces to be processed with only steam. The second ejector 30 can? It can also be used to carry out a treatment of the pieces with steam and abrasive, in particular useful for polymer pieces where the heat helps to reduce the surface mechanical resistance.

This second ejector 30 can? it can also be used to clean the tank 50 and the vibrofinishing media at the end of the cycle. Figure 4 ? a top view of an ejector 20 belonging to the machine of the invention and figure 5 ? a sectional view along the plane A-A of Figure 4 of the ejector 20.

The ejector 20 has a first channel 22 for the inlet of steam under pressure and a second channel 24 for the inlet of a working fluid for the pieces to be machined.

The first channel 22 and the second channel 24 flow into a Venturi tube 26 which ends with an outlet nozzle 28.

The pressurized steam, which acts as the driving product, and the working fluid, which can also be defined as trailed product, they mix in a venturi tube 26 and are directed towards the workpieces, coming out of a nozzle 28.

In one embodiment of the invention, the working fluid is a coloring liquid and, as better illustrated below, the machine of the invention? used to color workpieces.

The steam used? preferably dry saturated steam at relatively high pressures but with low flow rates, for example 1.25 l/h for each kW used.

Pi? in general, the towed product pu? to be:

a) Coloring liquid for dyeing polymers, fabrics or other materials (but it could also not be liquid, therefore a gel or granular powders, or emulsions, or other physical states)

b) Abrasive gel

c) Slurry, or 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.

From the outlet nozzle 28 there is the mixture generated by the driving steam and by the driven product.

Are there various methods? drain for the fluids contained in the work tank.

The discharge takes place via the automatic, pneumatically controlled discharge valve 42 outside the machine, where a linear actuator allows the discharged wastewater to be directed to three different destinations.

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

The discharge into the recycling tank 44, for subsequent reuse in one or more? times, depending on the case, e.g. for the reuse of the water/detergent solution [tank with booster pump).

The discharge into the wastewater storage or recovery tank 46, for wastewater destined for disposal.

As regards the steam dyeing of pieces, according to one embodiment of the invention, it can be compared to the classic hot water immersion dyeing process with solution dye.

COMPARISON EXAMPLE ACCORDING TO KNOWN TECHNIQUE

A classic application example, relating to a well-known hot water immersion dyeing process with dye in solution, is the following.

to. Consider a medium-small heated stainless steel tank (eg a tank for ultrasonic cleaning is commonly used) in which to immerse a product at 80?C for 2 minutes, or a tank with a capacity of equal to 30 liters;

b. Consider that the percentage of colorant to obtain a result is 1 to 9 - therefore 1 part of colorant (rather expensive) is needed for every 9 parts of water, therefore 3 liters of color in the tank with 27 liters of water.

c. Once the temperature of 80?C has been reached, the pieces to be immersed must be left to remain for 2 minutes, then they must be removed and drained.

The liquid with the color will be able to be reused for a few times. EXAMPLE 1

Let us now consider an application example in which the system of the invention is used, in which ? present a jet of steam suitably additived with dye, such as to involve a component or a piece to be worked in a three-dimensional way on its entire surface.

Will we see? that the process of the invention allows to obtain the desired result with less use of dye.

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

Inside the vibrating tank 50, the pieces to be worked (alone or helped by special light elastic inserts or vibrofinishing media) are placed in rotation, or in any case in movement according to a rolling motion so that they expose their surfaces in the different directions of space and, as the first phase of the process, they are brought to a temperature of 80°C through the ejector 30.

There? happens while the pieces to work pass more? times under the jet of dry saturated steam generated by the thermal group 70.

Once the optimal temperature has been reached, the in-line vacuum generator 20 comes into action (while the previous jet of the ejector 30 stops) and this? determines the supply of steam with dye additive, by sucking the ink contained in the container 40 along a conveying line or tube 40? (or through another container and any optional precision pump 60).

In particular, the dry saturated steam generated by the thermal group 70 is conveyed to the in-line vacuum generator 20 by means of a conveying line 20?, while on the other hand the dry saturated steam 70 is conveyed to the ejector 30 by means of a conveying line 30?. Being the steam flow rate equal to 4 l/h and being the feeding ratio equal to about 2/10, it is obtained that, at the most, in a time of 60 minutes, the additived dye will be able to be 4l/10 x 2 = 0.8 litres. However, since the time required for coloring could vary between the same amount of time with respect to the classic immersion phase at double this time, we will obtain that instead of 2 minutes it will also take from 3 to 4, with a consumption, for example, 0.8/60 x 4 = 0.0533 liters (the liquid condensed in the tank can be discharged and recovered).

It is concluded that, to obtain the tincture of pi? or less the same amount? of artifacts, the system of the invention compared to the classic one, uses 0.1 liters of dye instead of? 3 litres, i.e. a ratio of approximately 30 times less.

Even if this ratio were to vary, you can? to affirm statistically that the system of the invention offers the possibility? to reduce dyestuff consumption by at least 10 times in a dyeing process, compared to conventional methods.

It is not excluded that, at the end of pi? steam dyeing cycles according to the invention, before carrying out a color change, for example, the use of the ejector 30, this time fed not only with the steam from the same generator, but also with abrasive gel or slurry (water/ abrasives) by means of the peristaltic pump 73, is extremely useful for cleaning the tank and any elastic media (or vibratory finishing media) contained therein. This automatic cleaning process creates an effective environment which, after a simple rinse (recycled, through a tank with pump 44? or with water from the flowmeter with solenoid valve 71, or with the addition of liquid chemical compound through electric pump 72 ), ? ready to receive new coloring items, with a new tint or color.

In particular, the feeding of the abrasive gel or slurry (water/abrasive mixture) via the peristaltic pump 73 to the ejector 30 takes place thanks to the conveying line 73?.

Furthermore, the water coming from the flowmeter with solenoid valve 71 is conveyed to the working tank 50 by means of a conveying line 71?, while instead the liquid chemical compound sent to the working tank 50 by means of an electric pump 72 is conveyed by means of a conveying line 72?.

A first possibility? of the invention ? that of using a vibrating process tank 50 mounted on springs 51, which ? vibrated by a motor, as in figures 1-3.

In this tank 50, the pieces to be machined rotate three-dimensionally inside a toroidal tank and are exposed, in addition, passages, to the steam-activated sandblasting jet, by means of an ejector 30, allowing texturing and in any case exposure on each side gradually exposed until 100% involvement of the surface is reached.

In this operational dynamic? Is it possible to operate even with low volumes of pieces to be steam sandblasted, thanks to the appropriate use of vector media ? elastic or non-elastic preforms, able to perform the dual function of three-dimensionally orienting the pieces to be machined and, on the other hand, to avoid or contain their shocks.

Well, according to this same principle, the workpieces subjected to the steam jet are gradually involved on each side of the surface, so 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/finely abraded, involved or treated with dry saturated steam, suitably additived with:

the. Abrasive gel

ii.Slurry, or set of liquids and solid substances in granules, granular abrasives

iii. Liquid non-abrasive chemical substance or compound (e.g., detergent)

iv. Non-abrasive gel-like chemical substance or compound (e.g. flux).

According to the previously described principle of steam dyeing, the pieces to be worked are colored or involved or treated with dry saturated steam, suitably additived with dye, via the ejector 20 instead of with the 30, until obtaining the desired dyeing of the surface.

Alternatively, instead of the vibrating tank 50, ? It is possible to use a different dynamic for the pieces to be machined, or a dynamic referring to the use of a rotating tumbler instead of a circular vibro-finishing machine.

This system makes it possible to achieve similar results, proposing similar movements of the mass with respect to the points where the steam is introduced, steam and color or steam and gel.

A further embodiment of the invention envisages its use in rectangular or linear vibratory finishing machines, with which, suitably configured, it? possible to achieve similar results. A further variant of the invention provides an operating principle according to which ? possible, as an alternative to the other dynamics already? described:

Orient with a system of controlled axes (CNC) each single workpiece, group or cluster of workpieces or frame with multiple? workpieces, directing them towards a fixed point in which ? active the outlet point of the jet of steam cos? determining, depending on the type of steam jet and principle that is activated in the machine:

According to the same principles indicated above, the components are sandblasted or involved or treated with dry saturated steam, suitably additived with:

to. Abrasive gel

b. Slurry, or set of liquids and solid substances in granules, granular abrasives

c. Coloring liquid (or gel) for dyeing polymers, fabrics or other materials

d. Liquid non-abrasive chemical substance or compound

And. Non-abrasive chemical gel substance or compound.

Or orient with a system of controlled axes (CNC) the ejector with steam jet, towards each single workpiece, group or cluster of workpieces or frame with multiple? pieces being processed suitably fixed, so as to involve all the required surfaces with the jet of steam, so determining, depending on the type of steam jet and principle that is activated in the machine:

According to the same principles indicated above, the components are sandblasted or involved or treated with dry saturated steam, suitably additived with:

to. Abrasive gel

b. Slurry, or set of liquids and solid substances in granules, granular abrasives

c. Coloring liquid (or gel) for dyeing polymers, fabrics or other materials

d. Liquid non-abrasive chemical substance or compound

And. Non-abrasive chemical gel substance or compound.

A further variant of the invention provides the operating principle according to which ? possible and/or preferable, as an alternative to the other dynamics described:

Orient with a ROBOT (Scara or anthropomorphic) or COBOT every single component, group or cluster of components or frame with multiple? components, directing it / s towards a fixed point in which ? active the outlet point of the jet of steam cos? determining, depending on the type of steam jet and principle that is activated in the machine:

According to the same principles indicated above, the components are sandblasted or involved or treated with dry saturated steam, suitably additived with:

to. Abrasive gel

b. Slurry, or set of liquids and solid substances in granules, granular abrasives

c. Coloring liquid (or gel) for dyeing polymers, fabrics or other materials

d. Liquid non-abrasive chemical substance or compound

And. Non-abrasive chemical gel substance or compound

Or orient with a ROBOT (Scara or anthropomorphic) or COBOT l? ejector with steam jet, towards a single component, group or cluster of components or frame with more? components suitably fixed, so as to involve all the required surfaces with the jet of steam so? determining, depending on the type of steam jet and principle that is activated in the machine:

According to the same principles indicated above, the components are sandblasted or involved or treated with dry saturated steam, suitably additived with:

to. Abrasive gel

b. Slurry, or set of liquids and solid substances in granules, granular abrasives

c. Coloring liquid (or gel) for dyeing polymers, fabrics or other materials

d. Liquid non-abrasive chemical substance or compound

And. Non-abrasive chemical gel substance or compound.

Obviously all? invention cos? as described, modifications or improvements may be made for contingent or particular reasons, without thereby departing from the scope of the invention.

Claims (9)

1. Machine (10) for steam treatment of surfaces, where the aforementioned machine (10) comprises at least one process tank (50) for containing the pieces to be processed, where the aforementioned tank (50) ? applied at least one ejector comprising a first channel (22) for the inlet of steam under pressure and a second channel (24) for the inlet of a working fluid for the pieces to be processed, where the first channel (22) and the second channel (24) flow into a Venturi tube (26) which ends with an outlet nozzle (28), where a mixture of steam and the working fluid comes out from the aforementioned outlet nozzle (28) and where this mixture ? directed on the workpieces to change the state of the surfaces of the aforementioned workpieces. 2. Machine (10) as per claim 1, in which the second channel (24) for the entry of the working fluid can? be used for a working fluid chosen from a coloring liquid for dyeing polymers, or for dyeing fabrics or other materials. 3. Machine (10) as per claim 1, wherein the second channel (24) for the entry of a working fluid can? be used for abrasive gel, slurry, or mixture of liquids and solids in granules, granular abrasives, liquid non-abrasive chemical compounds or gel non-abrasive chemical compounds. 4. Machine (10) as claimed in claim 1, wherein ? foreseen supply of water to said process tank (50) for washing the tank itself. 5. Machine (10) as claimed in claim 1, wherein the process tank (50) is mounted on springs (51) and ? made to vibrate by an engine and ? configured in a circular or toroidal shape and to contain the workpieces inside. 6. Machine (10) as claimed in claim 1, wherein the process tank is configured in the form of a rotating tumbler or as a rectangular or linear vibrofinishing tank. 7. Machine (10) as claimed in claim 1, wherein ? Is there a system of controlled axes (CNC), or a ROBOT (Scara or anthropomorphic) or a COBOT to orient each single piece being processed, group or cluster of pieces being worked on or a frame equipped with multiple? workpieces, directing them towards a fixed point in which ? active outlet point of the steam jet or to direct the ejector with steam jet, towards each single workpiece, group or cluster of workpieces or frame with multiple? workpieces properly fixed. 8. Process for the steam treatment of surfaces of pieces being processed inside a process tank (50), where the aforementioned process comprises at least the following steps: - imposing a rolling motion on the aforesaid workpieces in such a way that they expose their surfaces in the different directions of space; - use of a working fluid mixed with pressurized steam to create a mixture to be ejected against the surfaces of the pieces being processed inside the process tank (50) to modify the state of the surfaces of the aforementioned pieces being processed. 9. Process as claimed in claim 8, wherein ? a pre-treatment phase of the pieces being processed inside the process tank (50) is provided, in which the aforementioned pieces are treated with pressurized steam.