WO2014177898A1

WO2014177898A1 - A method for brushing at least one metal tubolar member and relevant brushing device

Info

Publication number: WO2014177898A1
Application number: PCT/IB2013/000823
Authority: WO
Inventors: Umberto BIANCHI
Original assignee: Martinenghi S.R.L.
Priority date: 2013-05-02
Filing date: 2013-05-02
Publication date: 2014-11-06
Also published as: EP2991803A1; CN105408061A; WO2014177898A8

Abstract

Method for brushing at least one metal tubular member (100), comprising the step of a) abrading the outer surface of said at least one metal tubular member and, simultaneously, the step of b) removing the metal powders produced during said step a) of the method, characterized in that said step b) comprises the step of c) delivering a flow of atomized fluid at least in correspondence to the outer surface (100a) of said at least one metal tubular member (100) in order to at least temporarily keep suspended, in said flow of atomized fluid, the metal powders produced during said step a) of the method.

Description

"A method for brushing at least one metal tubular member and relevant brushing device"

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FIELD OF THE INVENTION

The present invention relates to a method for brushing at least one metal tubular member, particularly made of aluminium or alloys thereof, and a relevant brushing device.

KNOWN PREVIOUS ART

According to the prior art, metal tubular members comprising, for example, cylindrical metal containers such as tubes, cans or cylinders, usually made of aluminium and used to contain fluid (for example gaseous) or semi-fluid products (such as pastes), are obtained by a cold extrusion process followed by an operation of brushing the outer surface thereof.

Usually, this brushing operation serves a dual purpose: obtaining a pleasing aesthetic effect on the external surface and improving the adhesion of a subsequent layer of lacquer applied to the outer surface of the metal tubular member.

Traditional cylinders or beverage cans are brushed by employing a dry mechanical process usually using a rotating circular brush, which acts on the outer surface of these metal tubular containers. The rotating brush is supported by a pin, which is rotated integrally with the brush itself. The brushing operation leads to the generation of metallic powders, which are removed by suction means provided with special water filters in order to increase the efficiency of the brushing operation and, in case of powders of aluminium or alloys thereof, to simultaneously minimize the risk of explosion due to the oxidation of aluminium powder.

In the last years, the need for reducing the weight of cylinders or beverage cans, and therefore the production costs therefor, prompted the research to develop lightweight containers, i.e. containers having a reduced wall thickness, thereby leading to the use of alloys having an internal pressure resistance capability which is at least equal to that assured by traditional extruded cylinders or cans made of pure aluminium.

The technology for the manufacture of these thin- walled cylinders or cans usually involves using sheet plates made of a suitable aluminium (or other metal) alloy, which are deformed by deep-drawing and drawing to obtain the desired size. The deep-drawing and drawing process is performed in a cooling and/or lubricating environment normally obtained by contacting a water-oil emulsion with the material to be deep-drawn and drawn, the water/oil ratio being variable.

Therefore, the tubular member obtained by the forming process is wet with the cooling and lubricating fluid. In view of the above, the traditional brushing process resulting in a considerable generation of aluminium (or other metal) powders with a fine particle size, as said above, has eventually shown to be inadequate because a metal surface wet with a water - mineral oil emulsion does not generate a powder but a sludge of aluminium (or other metal).

The sludge is formed in significant amounts, thereby not allowing the brushing device to operate more than a few hours. In fact, the sludge quickly dirties the mechanical elements and penetrates the components of the device, resulting in the jamming thereof. Even when the water - mineral oil emulsion existing on the outer surface of the metal cylinder or can is intended to be removed before carrying out the brushing operation, the brushing device should be provided with a drying oven, and possibly with a pre-washing station, upstream of the brushing device. This would lead to a significant increase in complexity of both the brushing device and the method for the production of traditional metal cylinders or cans, as well as to an increase in energy consumption and overall bulk of the system for the production of these metal tubular containers.

Accordingly, current methods for brushing cylinders, cans or other metal tubular members obtained in a lubricating and/or cooling environment, i.e. preferably obtained by deep-drawing and drawing, are ineffective because they either compromise the functionality of the brushing device used or significantly increase the complexity of both the usually used brushing device and the system for the production of such metal cylinders in order to obtain satisfactory end results.

However, more generally, there are no methods and relevant devices for brushing a metal cylinder, or can, which can provide an effective brushing of such metal tubular members while being relatively simple and inexpensive in terms of resource consumption. Therefore, an aim of the present invention is to implement a method and a relevant device for brushing a metal tubular member in an effective, technically simple manner and with a reduced consumption of resources.

Additionally, an aim of the present invention is to implement a method for brushing a metal tubular member, preferably obtained in a cooling and/or lubricating environment, for example by deep-drawing and drawing or by other similar method, in a technically effective manner while preventing the brushing device used from getting jammed.

A further aim of the present invention is to implement a brushing device which is structurally simple and reduced in overall dimensions.

SUMMARY OF THE INVENTION

These and other aims are achieved by the present method for brushing at least one metal tubular member, comprising the step of a) abrading the outer surface of said at least one metal tubular member and, simultaneously, the step of b) removing the metal powders produced during said step a) of the method, characterized in that said ste b) comprises the step of c) delivering a flow of atomized fluid at least in correspondence to the outer surface of said at least one metal tubular member in order to at least temporarily keep suspended, in said flow of atomized fluid, the metal powders produced during said step a) of the method.

Therefore, practically, once the metal tubular member, preferably made of aluminium or an alloy thereof, has been formed and brushed, unlike the brushing method of the prior art, the outer surface of the tubular member is sprayed with a flow of atomized fluid, i.e. finely dispersed droplets of said fluid, preferably but not limited to water or water in admixture with certain additives such as mechanical processing-grade oils, mineral oils, mineral oil-based emulsions or other additives commonly known as "cooling agents" (or "coolants"), thereby at least temporarily keeping suspended, in said flow of atomized fluid, the powders produced during the step of a) abrading the outer surface of said at least one tubular member.

In fact, the Applicant has found that the ultra-fine metal powders resulting from brushing the surface of the metal tubular member are entrapped within the finely dispersed droplets of atomized fluid directed towards the surface of the tubular member. In this way, by collecting the flow thus established of atomized fluid, it is possible to remove the metal powder particles, particularly made of aluminium or an alloy thereof, from the brushing area, i.e. from near the metal tubular member being processed. This prevents the metal powder from remaining near the cylindrical member being processed in the form of sludge, i.e. a mixture of powder and cooling liquid, which may deposit on the surface of the cylindrical member.

Furthermore, according to a preferred embodiment of the invention, subsequent to said step c), there is provided the step of d) moving away and/or removing the metal powders kept suspended in said flow of atomized fluid from said metal tubular member. In this step, therefore, the metal powders are flushed away and thus moved away or removed from the area in which the metal tubular member is brushed.

Also preferably, subsequent to said step d), there is provided the step of e) collecting said atomized fluid and said metal powders kept suspended in said atomized fluid in at least one collection tank. Furthermore, subsequent to said step e), there are provided the step of f) filtering the fluid collected in said at least one collection tank, and the step of g) atomizing said filtered fluid in order to use it in said step c) of the method.

Note that, according to a particular embodiment of the invention, said step a) is preceded by the step of forming said at least one metal tubular member in a lubricating and/or cooling environment. Preferably, but without limitation purposes, said step of forming said at least one metal tubular member is performed by deep- drawing and/or drawing. As a matter of fact, it is well known that such processes have to be carried out under a lubricating and/or cooling environment such as a water - mineral oil emulsion.

In this way, the entire brushing method is carried out in a wet or moist environment, thereby not requiring the metal tubular member to be washed and dried after the production thereof in a lubricating and/or cooling environment of the previous step, as would be necessary with the known brushing methods. This avoids the need of suitably oven-drying the metal tubular members formed by deep-drawing and drawing before subjecting them to brushing. Then, in the step of delivering a flow of atomized fluid around and near the outer surface of the metal tubular member being working, the metal powders are kept suspended in said atomized fluid and then discharged therewith, thus preventing them from forming a sludge which is difficult to be disposed of.

According to a preferred embodiment of the method according to the present invention, said flow of atomized water is directed substantially towards the outer surface of the metal tubular member. Particularly, such delivery is preferably carried out from an upper position to a lower position with respect to said at least one metal tubular member.

The aims of the invention are also achieved by a device for brushing at least one metal tubular member, having means for abrading the outer surface of said at least one metal tubular member and means for removing the metal powder produced by said abrading means, characterized in that said removing means comprise as well means for delivering a flow of atomized fluid at least in correspondence to said outer surface of said at least one metal tubular member in order to at least temporarily keep suspended, in said flow of atomized fluid, the powders produced by said abrading means.

According to the specific embodiment described herein, said means for delivering the flow of atomized fluid, particularly atomized water, comprise one or more nozzles, and said at least one brushing device is provided with means for atomizing said fluid which can be connected to said one or more nozzles. Additionally, said at least one brushing device comprises at least one tank for collecting the atomized fluid and the powders kept suspended in said flow of atomized fluid; said at least one tank is arranged below said at least one metal tubular member. Furthermore, said at least one collection tank comprises one or more filters for filtering the fluid collected in said at least one collection tank, and means for fluidically connecting said at least one tank with said atomizing device. This can allow the atomized fluid initially directed towards the external surface of said metal tubular member to be reused. According to a particular embodiment of the invention, said abrading means comprise at least one rod conveyor for dragging said at least one metal tubular member through said at least one device, at least one friction belt for rotating said at least one metal tubular member, and at least one abrasive belt for brushing the outer surface of said at least one metal tubular member, wherein said at least one friction belt and said at least one abrasive belt are respectively arranged below and above said at least one metal tubular member, or vice versa, at least when said at least one metal tubular member is dragged through said brushing device by said at least one rod conveyor.

Additionally, according to a further embodiment of the invention, the device also comprises means for varying the distance and/or angle between said at least one abrasive belt and said at least one metal tubular member.

Finally, the aims set forth above are also achieved by a system for the production of at least one metal tubular member, comprising at least one forming device for forming said at least one metal tubular member, at least one device according to one or more of claims 10 to 15 for brushing said at least one metal tubular member, and means for transferring said at least one metal tubular member from said at least one forming device to said at least one brushing device. Particularly, said at least one forming device comprises at least one deep-drawing and/or drawing device or otherwise a forming device operating in a lubricating and/or cooling environment. BRIEF DESCRIPTION OF THE FIGURES

For purposes of illustrations and not limitative, a particular embodiment of the present invention will be described with reference to the accompanying figures, in which:

figure 1 is a schematic side view of the device for brushing at least one metal tubular member according to the invention;

figure 2 is a schematic side view of the system for forming at least one metal tubular member according to the invention;

figure 3 is a perspective view of a metal tubular member.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE PRESENT INVENTION

With particular reference to these Figures, a brushing device according to the invention is referred to by reference numeral 1. In Figure 1 there is shown a device 1 for brushing one or more metal cylinders or tubes, i.e. metal tubular members, which are preferably made of aluminium or an aluminium alloy.

Note that, for simplicity's sake, particular reference will be made hereinafter to the brushing of metal cylinders preferably made of aluminium or an alloy thereof, however, it is understood that the device, method and system according to specific embodiments of the present invention as described below are equally applicable to any metal tubular member and particularly to any metal container such as, for example, a cylinder intended to contain gaseous or aerosolized fluids, or a can intended to contain beverages.

According to the particular embodiment described herein, since each metal cylinder 100 is produced in a lubricating and cooling environment, its outer surface 100a is wet with a water - mineral oil emulsion.

It should be observed that, although the term lubricating and/or cooling environment is hereinafter intended to mean a water - mineral oil emulsion, however, the scope of protection of the present invention also includes a lubricating and/or cooling environment obtained with another type of emulsion and/or mixture of one or more components, or generally with any fluid suitable for such purposes. Note also that, although reference will be made hereinafter to a metal tubular member produced in a lubricating and/or cooling environment, however the brushing method, the brushing device and the system for the production of metal tubular members - which are the subject matters of this invention - can all be used with metal tubular members produced by any other processing method, possibly also a dry-processing method, without departing from the scope of protection of the present invention.

Such a brushing device 1 comprises means 2 for abrading the outer surface 100a of a general metal cylinder 100 made of aluminium or an alloy thereof, and means 3 for removing the metal powder produced by said abrading means 2 when the outer surface 100a of the above metal cylinder 100 is being brushed. Advantageously, the removing means 2 also comprise means 4 for delivering a flow of atomized fluid to the outer surface 100a of the cylinder 100 made of aluminium or an aluminium alloy in order to at least temporarily keep suspended the powders produced by said abrading means 2 in said flow of atomized fluid, thereby causing the powders to be moved away from the outer surface of the metal cylinder 100. In the embodiment described herein, such a fluid is water and, therefore, the flow of atomized fluid comprises atomized water. According to an alternative embodiment, said fluid can also be water in admixture with additives such as a general volatile lubricant, oils, soaps, waxes or the like as known in the art, without departing from the scope of protection of the present invention.

More specifically, said means 4 for delivering the flow of atomized water comprise a plurality of nozzles which are fluidically connected to appropriate means 6 for atomizing water. These atomizing means 6, which are incorporated in the brushing device 1, are well known in the art and therefore not further described in detail. The nozzles 4 are arranged above the metal cylinder 100 to be brushed, and the flow of atomized fluid is directed downwards so as to follow a substantially vertical path. Practically, the abrasion area is continuously sprayed with such a fluid through said nozzles 4, which act to keep clean the processing area by at least temporarily keeping suspended the powder resulting from the abrasion of the outer surface 100a of the metal cylinder 100 in the atomized fluid itself, and then removing it from the cylinder.

Also with reference to Figure 1, the brushing device 1 comprises a tank 7 for collecting the atomized fluid and the powders kept suspended in said flow of atomized fluid. Such a tank 7 is advantageously arranged below the metal cylinder 100 so as to easily collect the atomized water loaded with the metal particles of ultra- fine powder resulting from the abrasion of the outer surface 100a of the metal cylinder 100 by said abrading means 2.

Furthermore, the collection tank 7 comprises a filter 25 for filtering the fluid collected in the collection tank 7, and means 8 for fluidically connecting the tank 7 and the atomizing means 6 to each other. In this manner, the working fluid can be continuously recovered while the cylinder 100 is being brushed, thus avoiding an undue consumption of fluid and energy. In fact, the nozzles 4 are connected to the atomizing means 6 through an appropriate fluid connection line 15. More specifically, according to the embodiment of the present invention as described herein, said abrading means 2 comprise a rod conveyor 10 for dragging the metal tubular member (cylinder) 100 to be brushed through the brushing device 1, two friction belts 11 for rotating the metal cylinder 100 while it is conveyed by the above mentioned conveyor 10, and two abrasive belts 12 for brushing the outer surface 100a of the metal cylinder 100.

The two friction belts 11 and the two abrasive belts 12 are preferably arranged below and above the metal cylinder 100, respectively, at least when the cylinder 100 is dragged through the brushing device 1 by said rod conveyor 10.

Note that, although a brushing device 1 is shown herein in which the friction belts 11 are arranged in a lower position and the abrasive belts 12 are arranged in an upper position, however, it is understood that any other mutual arrangement can be possible, for example, an arrangement in which the abrasive belts are in a lower position and the friction belts are in an upper position, without departing from the spirit of the present invention.

Note also that the numbers of friction belts 11 and abrasive belts 12 can be varied as a function of the processing speed to be achieved in order to perform the brushing operation within a reasonable time. Indeed, the hardness of the used material, i.e. aluminium, aluminium alloys or the like, requires a rather long processing time in order to obtain an appropriate brushing quality, so that the device may need to be equipped with multiple successive stations, i.e. with multiple pairs of friction belts and abrasive belts arranged sequentially next to each other. In view of the above, although not described herein, a brushing device 1 either equipped with one friction belt 11 and one abrasive belt 12 or else equipped with more than two friction and abrasive belts, i.e. provided with multiple processing stations within the brushing device, nevertheless still falls within the scope of protection of the present invention. Finally, the device 1 comprises means (not shown herein) for varying the distance and/or angle between the abrasive belt 12 and said metal tubular member (cylinder) 100. In this way, it is possible to adjust the position of the abrasive belt 12 in order to allow the machine to be used for the production of containers having different diameters. Additionally, this adjustment allows the brushing pressure to be set, thereby affecting the aesthetic effect that is desired for a specific product.

In Figure 2 there is also shown a system 20 for the production of a metal tubular member 100, which comprises a device 21 for forming said metal tubular member 100 in a lubricating and/or cooling environment, a device 1 of the type described above for brushing said metal tubular member 100, or in any case a brushing device as claimed in one or more of claims 10 to 15, and means 22 for transferring said metal tubular member 100 from said forming device 21 to said brushing device 1. According to the embodiment described herein, the forming device 21 comprises a deep-drawing and/or drawing device which is only schematically depicted herein, as it is well known in the art of production of metal cylinders or metal tubular members. Note that, as also anticipated above, the forming device 21 may also be of a known type, i.e. provided with cold-extrusion means and therefore operating in a dry environment, without departing from the scope of protection of the present invention. According to the invention, the method for brushing a metal tubular member 100 preferably made of aluminium or an alloy thereof and produced, for example, in a lubricating and/or cooling environment comprises the step of a) abrading the outer surface 100a of the metal tubular member 100 and, simultaneously, the step of b) removing the metal powders produced during said step a) of the method. Advantageously, said step b) comprises the step of c) delivering a flow of atomized fluid, particularly atomized water, to the outer surface 100a of the metal tubular member 100 in order to keep suspended the metal powders produced during said step a) of the method in said flow of atomized fluid.

Specifically, said step a) is preferably preceded by the step of forming said metal tubular member 100 by deep-drawing and/or drawing although, alternatively, it may be preceded by a step of forming the metal tubular member 100 by extrusion.

Note that, as anticipated above, such a method can also be adapted for use in brushing metal tubular members which are dry because they were produced in a non- wet environment or subjected to a preliminary drying operation, without departing from the scope of protection of the present invention. Additionally, subsequent to said step c) of the method, there is provided the step of d) moving away and/or removing the metal powders kept suspended in said flow of atomized fluid from said metal tubular member 100.

Furthermore, said step d) comprises the step of e) collecting said atomized fluid and said metal powders kept suspended in said atomized fluid in a collection tank 7. Subsequent to said step e), there are provided the step of f) filtering the fluid collected in said collection tank 7, and the step of g) atomizing said filtered fluid in order to reuse it in said step c) of the method. According to the embodiment described herein, said flow of atomized fluid is substantially directed towards said at least one metal tubular member 100 and particularly, according to a preferred embodiment of the invention, from an upper position to a lower position with respect to the metal tubular member 100. Therefore, the collection tank 7 is arranged below the metal tubular member 100 in order to collect the flow of atomized fluid which has been delivered to the outer surface 100a of the metal tubular member 100.

It should be noted that, according to the particular embodiment described herein, said lubricating and/or cooling environment comprises a water and/or mineral oil emulsion.

Claims

1) Method for brushing at least one metal tubular member (100), comprising the step of a) abrading the outer surface of said at least one metal tubular member and, simultaneously, the step of b) removing the metal powders produced during said step a) of the method, characterized in that said step b) comprises the step of c) delivering a flow of atomized fluid at least in correspondence to the outer surface (100a) of said at least one metal tubular member (100) in order to at least temporarily keep suspended, in said flow of atomized fluid, the metal powders produced during said step a) of the method.

2) Method according to claim 1, characterized in that, subsequent to said step c), there is provided the step of d) moving away and/or removing the metal powders kept suspended in said flow of atomized fluid from said metal tubular member.

3) Method according to one or more of the preceding claims, characterized in that, subsequent to said step d), there is provided the step of e) collecting, in at least one collection tank, said atomized fluid and said metal powders kept suspended in said atomized fluid.

4) Method according to claim 3, characterized in that, subsequent to said step e), there are provided the step of f) filtering the fluid collected in said at least one collection tank, and the step of g) atomizing said filtered fluid in order to use it in said step c) of the method.

5) Method according to claim 1 or 2 or 3 or 4, characterized in that said step a) is preceded by the step of forming said at least one metal tubular member in a lubricating and/or cooling environment.

6) Method according to claim 5, characterized in that said step of forming said at least one metal tubular member is performed by deep-drawing and/or drawing.

7) Method according to one or more of claims 1 to 6, characterized in that said at least one metal tubular element is made of aluminium or an alloy thereof.

8) Method according to one or more of the preceding claims, characterized in that said flow of atomized fluid is substantially directed towards said at least one metal tubular member. 9) Method according to one or more of the preceding claims, characterized in that said atomized fluid comprises at least atomized water.

10) Device (1) for brushing at least one metal tubular member, having means (2) for abrading the outer surface of said at least one metal tubular member and means (3) for removing the metal powder produced by said abrading means, characterized in that said removing means comprise as well means (4) for delivering a flow of atomized fluid at least in correspondence to said outer surface (100a) of said at least one metal tubular member (100) in order to at least temporarily keep suspended, in said flow of atomized fluid, the powders produced by said abrading means.

11) Device according to claim 10, characterized in that said means (4) for delivering the flow of atomized fluid comprise one or more nozzles (5), said at least one brushing device being provided with means (6) for atomizing said fluid which can be connected to said one or more nozzles.

12) Device according to claim 10 or 11, characterized by comprising at least one tank (7) for collecting the atomized fluid and the powders kept suspended in said flow of atomized fluid, said at least one tank being arranged below said at least one metal tubular member (100).

13) Device according to claim 12, characterized in that said at least one collection tank comprises one or more filters for filtering the fluid collected in said at least one collection tank and means (8) for fluidically connecting said at least one tank to said atomizing means.

14) Device according to one or more of claims 10 to 13, characterized in that said abrading means (2) comprise at least one rod conveyor (10) for dragging said at least one metal tubular member through said at least one device, at least one friction belt (11) for rotating said at least one metal tubular member, and at least one abrasive belt (12) for brushing the outer surface of said at least one metal tubular member (100), said at least one friction belt and said at least one abrasive belt being respectively arranged below and above said at least one metal tubular member, or vice versa, at least when said at least one metal tubular member is dragged through said brushing device by said at least one rod conveyor. 15) Device according to claim 12, characterized by comprising means for varying the distance and/or angle between said at least one abrasive belt and said at least one metal tubular member.

16) System (20) for the production of at least one metal tubular member (100) comprising at least one forming device (21) for forming said at least one metal tubular member (100), at least one device (1) according to one or more of claims 10 to 15 for brushing said at least one metal tubular member, and means (22) for transferring said at least one metal tubular member from said at least one forming device to said at least one brushing device (1).

17) System according to claim 16, characterized in that said at least one forming device comprises at least one deep-drawing and/or drawing device.