WO2003078105A2

WO2003078105A2 - Method for stripping surfaces made of a metal or composite material covered with a coating and system for carrying out said method for stripping transport devices

Info

Publication number: WO2003078105A2
Application number: PCT/FR2003/000784
Authority: WO
Inventors: Antoine Pueyo
Original assignee: Aero Strip
Priority date: 2002-03-15
Filing date: 2003-03-12
Publication date: 2003-09-25
Also published as: WO2003078105A3; FR2837123B1; FR2837123A1; AU2003240928A8; AU2003240928A1

Abstract

The invention relates to a method for the stripping surfaces of a transport device which are made of a metal or composite material and which are covered with a coating (paint). The invention also relates to a system for stripping transport devices. According to the invention, a moveable, remote-controlled unit (10) moves along the transport device (50). Said unit is provided with a propulsion device (300) which propels a compressed air flow charged with cryogenic grains against the surface to be stripped, projecting said cryogenic grains at supersonic speed.

Description

METHOD FOR SCRAPING SURFACES OF METAL MATERIAL OR

COMPOSITE, COVERED WITH COATING AND IMPLEMENTATION SYSTEM

WORK OF THE PROCESS FOR THE STRIPPING OF TRANSPORT MACHINERY.

The invention relates to a method for pickling surfaces of metallic or composite material of transport equipment.

Among the metallic materials concerned, mention may be made of aluminum and steel. Among the composite materials, mention may be made of carbon fibers and resins.

Transport equipment, whether aircraft, boats or train cars, is covered with one or more layers of paint which it is necessary to maintain in condition because it (s) contributes (s) to protection of the surface of the machine.

This maintenance consists of periodically stripping the surface to remove the old weathered coating and repainting this surface. This is particularly important for aircraft given the constraints they face and the risks involved in the event of poor maintenance.

Certain stripping tools also allow the two operations to be carried out, ie the stripping operation and the painting operation. The stripping of a surface, when it is operated industrially poses the problem of pollution and the treatment of the waste obtained at the end of this operation. Today this question is taken into account by national and intergovernmental bodies and has resulted in regulations which in the coming decade must lead to the elimination of polluting techniques and aim for zero waste.

^• A further problem is encountered in the field of stripping of transport and especially for aircraft. This is the reduction in costs that can result from such operations.

The stripping operations of planes involve the immobilization of the equipment for too long periods with the procedures used to date and require having many replacement vehicles. We therefore understand the importance of reducing the cost of such operations, if only by reducing the downtime of the material to be stripped. For an aircraft, just one day of downtime represents a huge gain for the aviation company that operates the aircraft.

To date, several techniques are used to carry out the stripping of surfaces such as that of an airplane cabin or of any part made of composite or metallic material.

We will first of all cite stripping qualified as mechanical. This pickling is carried out by a technician using a conventional sander, that is to say a tool provided with an abrasive disc of relatively small diameter compared to the dimensions of the surfaces to be stripped. It is therefore usual for around fifteen people to intervene to strip the cabin of an airplane. Besides the large number of useful personnel, manual stripping has another drawback. The results obtained are of poor quality due to the imprecision of this technique. Indeed, it is impossible with a sander not to alter the support substrate of the coating since this coating is very thin as is the case of painting on an aircraft. The sander inevitably removes a layer of the substrate. This leads to premature wear of the material or even deterioration of certain parts, for example rivets, which raises safety concerns when damaged parts are not changed.

Another technique is also used to date, it is the chemical pickling. Chemical pickling provides good quality results.

However, the technique pollutes the environment, is harmful to the technicians who use it, and the costs are high.

In addition, in the case of stripping the cabin of an airplane, it takes 1,200 hours of work and six days of immobilization of the airplane. The duration of the operation and the number of days of immobilization are important elements in the cost of operating aircraft. This technique is costly for airlines. Mention may also be made of pickling techniques by projection of a plastic or starchy medium (starch). Indeed, the projection of a plastic medium causes an alteration of the surface condition and has been the subject of development to carry out the stripping of machines such as planes.

The projection of starchy media provides good results. However, in the two cases of projection of plastic or starchy media, we are in the presence of very large volumes of waste to be recycled. This technique causes discomfort in the work since fairly quickly a large mass of abrasive media and waste covers the ground around the machine. It is therefore necessary to provide means for decluttering the environment of the machine and, where appropriate, means for recycling product falling on the ground.

Another technique is also known, it is cryogenic pickling. According to this technique, particles of water ice (H20) or dry ice are projected (C02). In practical terms, the coating is softened with a chemical product and then ice or CO 2 particles are sprayed to remove the softened coating because the projection of the ice particles does not allow the surface to be scoured. It is necessary to have previously used a chemical softening paint.

This cryogenic pickling technique therefore consists of combining two pickling techniques, chemical pickling and mechanical pickling. It therefore has the drawbacks of chemical pickling: pollution of the environment.

In a neighboring technique, instead of being chemical, the softening is thermal. Flash or Xenon lamps are then used. It is not possible to envisage stripping large surfaces. This technique is ill-suited to an industrial operation which requires performance in time and cost.

Document DE 26 38 323 or DE 196 36 305 also knows a technique for cleaning surfaces using the projection of solidified particles by cooling, such as for example ice particles transported by a fluid or a gas subjected to a high pressure. The high pressure gives a flow velocity of the fluid or the spraying gas of 40 to 300 m / s maximum. These techniques do not allow the stripping of surfaces covered with material such as paint. They only allow the cleaning of a surface, ie the removal of dust or grease. The present invention overcomes these drawbacks.

The proposed process is non-polluting. It reduces the operating costs of transport equipment at stripped. For example, in the case of stripping of a medium-haul aircraft, the number of hours of stripping goes to 500 hours while the number of days of immobilization goes to 4 days. The invention provides a process compatible with industrial operation.

The invention also provides a stripping system having a great autonomy and not causing obstruction or obstruction of circulation for the operators who use this system.

Indeed the proposed system is entirely radio controlled and has its own energy source. It has sufficient reserves of abrasive product and compressed air leading to a limited number of stops for replenishment.

The proposed method uses spraying by means of a compressed air flow, cryogenic grains at spraying speeds significantly higher than the speeds encountered with known techniques. According to the invention the cryogenic grains are projected at supersonic speeds.

The pickling performance is better because thanks to these speeds the sublimation of the C02 particles is better.

The proposed technique is particularly suitable for pickling metal surfaces, especially aluminum.

In addition, the use of a supersonic speed makes it possible to provide better precision for pickling and to carry out pickling of a surface layer by layer if necessary. The device used for stripping can be placed with more shrinkage compared to conventional techniques which has the advantage of avoiding any confinement or heating of the treated surface. In addition, the air flow used does not need to be subjected to high pressure as in the prior art.

A more particular subject of the invention is therefore a method of stripping surfaces of metallic or composite material of a transport vehicle, covered with a coating mainly characterized in that it consists in propelling these surfaces by means of a flux of compressed air, cryogenic grains subjected to an acceleration so as to be projected at a supersonic speed.

Advantageously, the speed of projection of the cryogenic grains to scour planes is Mach 2.

According to another characteristic, the propulsion of the cryogenic particles is carried out on surfaces having an ambient temperature.

According to one embodiment, the cryogenic grains can be formed from 100% CO 2 particles.

According to a second embodiment, the cryogenic grains can be formed of CO 2 particles and of an additive consisting of synthetic or mineral particles.

In this second embodiment, the cryogenic grains may form an agglomerate of 100% CO 2 pushing an additive bonded to the surface of the agglomerate.

It may also be cryogenic grains formed from an agglomerate of C02 particles and additive (that is to say a mixture) obtained from a volume of 95% to 99% of C02 and respectively from 5% to 1% of additive.

Preferably, the cryogenic grains have a size (the greatest length) of the order of 500 μm to 3 mm. Preferably, the synthetic or mineral particles have a size of the order of about 150 to 500 μm.

Advantageously, the density of the particles in the flow of compressed gas which is used to propel them is 0.8 to 1.3. According to another characteristic, the compressed gas is dry air.

According to another characteristic, the air pressure is of the order of 1.5 bar, the flow rate of the order of 20000L / minutes, the power of the compressor being of the order of 50 CV. With this method, it is not useful to use compressed air having a high pressure as in the various known techniques.

Another object of the invention is a ^'system for pickling transport unit whose surface consists of a metallic or composite material coated with a coating mainly characterized in that it comprises at least one mobile unit capable to move along the machine, this mobile unit comprising a device for propelling cryogenic grains by means of a flow of compressed air and, for projecting these cryogenic grains at a supersonic speed.

According to another characteristic, the propulsion-projection device comprises: - a head for projecting the cryogenic grains speed accelerator, making it possible to reach a projection speed of Mach2.

According to another characteristic, the propulsion-projection device comprises: - a gas compressor providing a flow of compressed gas at the outlet,

- a cryogenic grain sprayer having a cryogenic grain feed inlet, an inlet connected by a pipe to the compressed gas outlet of the compressor, and an outlet for the flow of compressed gas loaded with cryogenic beans,

- a coupling pipe placed between an output of the sprayer and the input of the accelerator head. According to another characteristic, the accelerator head comprises a ramjet.

According to another characteristic, the designer comprises a die for the passage of compressed gas for transporting the grains and a die for the passage of a flow of fire gas, the two paths joining after the introduction of the cryogenic grains into the flow of compressed transport gas.

According to one embodiment, the designer comprises a reservoir of cryogenic particles, a device for forming cryogenic grains based on cryogenic particles and a device for adjusting the flow rate of the cryogenic grains introduced into the stream of compressed transport gas. In the case of use of synthetic or mineral additive particles, the pickling system comprises a reservoir of cryogenic particles, a reservoir of additive particles and a device for forming cryogenic grains based on cryogenic particles and particles of synthetic or mineral additive, the latter being in a proportion of 1 to 5% of the total volume.

In one embodiment, the device for forming cryogenic grains with additive is integrated in a chamber forming the two particle reservoirs, the. grains thus obtained consist of an agglomerate of cryogenic particles and additive particles, that is to say a mixture of particles.

According to another embodiment, the reservoir of additive particles is placed downstream of the sprayer and is coupled to the outlet pipe of the sprayer, the grains obtained consist of an agglomerate of particles. cryogenic to which the additive particles introduced into the flow circulating in the pipe adhere.

According to another characteristic, the mobile unit comprises a carriage provided with a telescopic arm carrying a nacelle in which is installed all or part of the propulsion device, a radio positioning device and sensors.

According to another characteristic, the system also comprises a cockpit for the carriage and real-time control of the pickling operation receiving the signals sent by the radio positioning device and by the sensors.

According to another characteristic, the radio positioning device provides the geographical coordinates of the projection head in real time, which makes it possible to obtain traceability of the pickling in space.

Provision is also made, in order to ensure a dry atmosphere and to avoid the formation of agglomeration of cryogenic grains, to place part or all of the propulsion device in a ventilated enclosure.

Other features and advantages of the invention will become clear on reading. the description which is given below by way of nonlimiting example and with reference to the drawings in which, FIG. 1A represents the general diagram of the pickling system according to the invention in one embodiment, FIG. 1B represents the diagram general of the pickling system according to the invention in a second embodiment, FIG. 1C represents the diagram of the interior of the nacelle in the case of the first embodiment, FIG. 2, the more detailed diagram of realization of the designer, FIG. 3, the diagram of realization of a device for forming cryogenic grains with additive according to a first embodiment, FIG. 4, the diagram of the device for forming cryogenic grains with additive according to a second embodiment, FIGS. 5 and 6, the diagrams of the grains obtained respectively according to the modes of embodiment illustrated in Figures 3 and 4;

The system according to the invention allows the stripping of transport vehicles, in particular planes, trains, boats and cars.

The description which follows and which is illustrated by the appended figures, is given from a particular example relating to the stripping of the cabin of an airplane.

The same system can be applied as we have just said to the stripping of any other means of transport.

The pickling process and the proposed system apply to surfaces made of a metallic material (aluminum, steel) or composite (carbon fibers, epoxy resin) covered with a coating. This coating is generally composed of an anti-corrosion paint and a finishing paint. It can also be dust or various types of dirt (grease, glued insects for example). The process is particularly effective for stripping in successive layers the coatings of aircraft cabins. In the example which is given and which is illustrated by the diagrams of FIGS. 1A and 1B, the pickling system comprises a single mobile unit 10 equipped with a telescopic arm 20 surmounted by a nacelle 30. It can of course be provided to use several mobile units if necessary to further reduce intervention times. Each mobile unit is remotely controlled by a cockpit 40. Advantageously, it is a radio control thus leaving the possibility of having a greater range, the station being able to be relatively far from the workshop in which the 'stripping machine.

In the first embodiment illustrated in FIG. 1A, the mobile unit or carriage 10 houses the sprayer 320 and the compressor 310 of the propulsion device 300 of a compressed air flow loaded with cryogenic grains, while the head of projection or nozzle 330 is in the nacelle 30 and is connected to the projector 320 by a pipe 327 which preferably runs along the telescopic arm 20. This pipe 327 has a length in the present case of 10m, the length being able to go according to the need 5 to 10m.

This embodiment allows easy reloading of cryogenic particles from the projector 320.

In the second embodiment shown in Figure 1B, the entire propulsion device 300 is placed in the nacelle. This embodiment can be chosen when the surface to be stripped is relatively small and therefore does not require a large volume of cryogenic particles (for example the stripping of inscriptions). In both embodiments, an electrical supply is provided in the carriage for all of the elements, this supply bears the reference 102. The propulsion device 300 is preferably placed in a ventilated enclosure 55 to ensure a dry atmosphere, apart from the projection head in the case of the first embodiment. The details of the elements placed in the nacelle are illustrated in FIG. 1B. The nacelle houses the projection head 330 of the propulsion device 300, the movement mechanism 60 of the projection head, the radio positioning device 70 of the head and a plurality of sensors 32.

The projection is carried out at a very high speed since these are supersonic speeds. In a practical example of stripping the cabin of an airplane, the projection speed of the cryogenic grains chosen is Mach 2. Thanks to the telescopic arm 20, the nacelle 30 is brought closer to the surface to be stripped until it comes into contact with it. ci and ensure a seal between the space thus closed and the outside. A seal 31 is placed around the window for this purpose. The contact is detected by sensors 32 placed around the window of the nacelle.

The cockpit 40 allows on the one hand to remotely control the movements of the mobile unit 10, to have real-time control over the stripping operation in progress and to control the movement mechanism 60 of the projection head 330.

To this end, the cockpit 40 is in connection with a radio positioning device 70 placed in the nacelle 30 and which is itself in relation with a geostationary satellite 80 so as to obtain a traceability of the pickling in the space to from the positioning coordinates, obtained by this device. The radio positioning device 70 supplies the geographical coordinates of the projection nozzle of the pickling, to the control unit 101 on board the carriage 100. This unit 101 is coupled to a transceiver 100 which enables it to communicate them to the control unit 40 by means of the radio link R. The wired link 103 symbolizes all the wired connections existing between the nacelle 30 and the mobile unit 10.

In addition, the cockpit 40 is linked to a radio command 41, which sends radio commands to the transceiver 100 placed in the mobile unit 10.

The mobile unit 10 can thus move along the machine and allow the pickling of the surface according to an established control program. This control program is loaded into the program memory of the data processing unit 42 of the control unit 40 and allows an operator to control the movement maneuvers of the mobile unit and of the projection nozzle, a camera 33 allowing him to control the pickling.

The control unit 40 can be produced by a PC type computer for example.

The piloting program is advantageously assisted by the radio positioning device 70 on board the nacelle 30.

The nacelle 30 also houses various sensors: contact sensor, and in particular the camera 32 which makes it possible to provide images of the area during stripping.

The nacelle also houses the mechanism 60 which makes it possible to move the projection nozzle in a coordinate plane

(x, y) facing the surface to be stripped, for example by means of electric motors allowing movement in a window 61.

We can now refer to the diagram in Figure 2 for the detail of the propulsion device. 300. This propulsion device comprises an air compressor 310 providing a flow of compressed air at the outlet, followed by a sprayer 320 which is followed by the projection head 330 which includes a statoreactor 332 ending in a spray nozzle 331 close to the wall to be stripped.

Advantageously, a very dry air compressor will be used. Preferably, the air pressure is of the order of 1.5 bars, it need not be higher. The flow rate is around 20000L / minute and the compressor power is around 50 CV.

The cryogenic grain sprayer 320 is connected to the air compressor 310 by a pipe 311. The pipe 311 is connected to the inlet 321 of the sprayer, intended for compressed air. This sprayer includes a chamber 303 or reservoir of cryogenic grains of sufficient capacity to ensure pickling cycles involving only a dozen grain filling operations. The tank has a capacity of 50 liters. An entry 321 is provided for filling.

Inside the sprayer 320, the chamber 303 therefore constitutes the reserve of cryogenic particles 322.

Inside the chamber 303, a system allows the formation of the grains. The grains consist of an agglomerate of particles. This system comprises an axis 304 which carries at one end of the blades 305 forming a cone. These blades are arranged opposite a grid 306. The grid is fixed in the lower part of the chamber. The axis is rotated by an electric motor 307 which therefore causes a rotational movement of the blades above the grid. The particles of the reserve are entrained by this movement and combine while passing through the grid. whose orifices are of suitable shape and dimensions to give grains of desired size.

The mechanism which has just been described is similar to the mechanism of a potato masher. The chamber 303 has an outlet 323 which is coupled to the compressed air circuit 324, 325. This circuit includes a die for the passage of compressed grain transport gas and a die for the passage of a flow of fire gas. two channels joining after the cryogenic grains have been introduced into the compressed gas transport stream.

The compressed air circuit therefore advantageously consists of two branches 324, 325 which join at their ends. One of the two branches, in the example, branch 324, conducts the compressed air for shooting and the branch

325 conducts compressed air for transporting cryogenic grains.

The flow of compressed air loaded with cryogenic grains leaves the sprayer via outlet 326. This outlet is connected by a pipe 327 to the projection head 330.

A valve 328 for adjusting the flow of the cryogenic grains introduced into the compressed air circuit is provided on the outlet of the chamber 322. The opening of this valve can be adjusted manually or electrically A valve 329 for adjusting the flow compressed air coming out of the sprayer is also provided on the pipe

327.

The projection head 330 used is an accelerator head. The cryogenic grains reach a supersonic speed. We will preferably choose a speed of the order of Mach 2 to strip the fuselage of an airplane when the grains used are made of carbon dioxide snow. Advantageously, the accelerator head is composed of a statoreactor.

In the description which has just been made, there have been cited by way of example as grains, grains consisting of particles of carbon dioxide snow (C02).

In the examples illustrated by FIGS. 3 and 4, the cryogenic grains are composed of CO 2 particles and of an additive. The additive consists of synthetic particles: recycled waste coated with resin, or mineral: talc.

To this end, the pickling system incorporates a grain formation device composed of cryogenic particles and additive particles.

In FIG. 3 illustrating a first embodiment of the grain formation device 400, 401,

402, 403, a reservoir 400 of synthetic or mineral additive particles is provided downstream of the sprayer

320.

The grains obtained by this device are illustrated by the diagram in FIG. 5. These grains consist of an agglomerate of cryogenic particles on which the particles of additive adhere when passing through the pipe.

327.

In Figure 4 there is shown a second embodiment for this device. In this case, the formation of cryogenic grains with additive, is carried out by elements integrated in the sprayer 320. The grains thus obtained consist of particles of CO 2 and of additive mixed as illustrated by the diagram in FIG. 6 .

In this case, the designer comprises a reservoir with two inlets 401, 321 making it possible to introduce the cryogenic grains 322 and of additive 402 forming the reserve. An axe 404 carries at one end of the blades 405 forming a cone, these blades are arranged opposite a grid 406. The grid is fixed in the lower part of the chamber. The axis is rotated by an electric motor 407 which thereby causes a rotation movement of the blades above the grid. The particles of the reserve are entrained by this movement and combine by passing through the grid, the orifices of which are of suitable shape and dimensions to give grains of desired size. In the two exemplary embodiments, the additive particles are in a proportion of 1 to 5% of the mixture.

The use of cryogenic grains with additive makes it possible to work if necessary with a reduced speed of projection between Machl ^' and Mach2.

Claims

1. A method of stripping surfaces of metallic or composite material of a transport vehicle, covered with a coating, characterized in that it consists in propelling cryogenic grains on these surfaces by means of a flow of compressed air. subjected to an acceleration so as to be projected at a supersonic speed.

2. The pickling method according to claim 1, characterized in that the projection speed of the cryogenic grains for pickling aircraft is Mach 2.

3. pickling method according to claim 1 or 2, characterized in that the propulsion of the cryogenic particles is carried out on 'surfaces having an ambient temperature.

4. pickling process according to claims 1 to 3, characterized in that the cryogenic grains are formed of 100% CO 2 particles.

5. pickling process according to claims 1 to 4, characterized in that the cryogenic grains are formed of CO 2 particles and an additive consisting of synthetic or mineral particles.

6. pickling method according to claim 4, characterized in that the cryogenic grains are formed of an agglomerate of 100% of CO 2 pushing an additive bonded to the surface of the agglomerate.

7. pickling method according to claim 5, characterized in that the cryogenic grains are formed of an agglomerate of CO 2 particles and of additive (that is to say of a mixture) obtained from a volume of 95% to 99% of C02 and respectively of 5% to 1% of additive.

8. pickling method according to any one of the preceding claims, characterized in that the cryogenic grains have a size (the greatest length) of the order of 500 μm to 3 mm.

9. A pickling method according to any one of the preceding claims, characterized in that the synthetic or mineral particles have a size of the order of about 150 to 500 microns.

10. A pickling method according to any one of the preceding claims, characterized in that the density of the particles in the stream of compressed gas which serves to propel them is 0.8 to 1.3.

11. pickling method according to any one of the preceding claims, characterized in that the compressed gas is dry air.

12. pickling method according to any one of the preceding claims, characterized in that the air pressure is of the order of 1.5 bar, the flow rate of the order of 20000L / minutes, the power of the compressor being of the order of 50 CV.

13. System for the stripping of transport equipment the surface of which is made of metallic material or composite covered with a coating, characterized in that it comprises at least one mobile unit (10) able to move along the machine (50), this mobile unit (10) comprising a propulsion device (300- 330) of cryogenic grains by means of a compressed air flow and, of projection of these cryogenic grains at a supersonic speed.

14. Pickling system according to claim 11, characterized in that the propulsion-projection device comprises:

- a projection head (330) of the accelerating cryogenic grains, making it possible to reach a projection speed of Mach2.

15. Pickling system according to claim 13 or 14, characterized in that the propulsion-projection device comprises:

- a gas compressor (310) providing a flow of compressed gas at the outlet,

- a cryogenic grain sprayer (320) having a cryogenic grain feed inlet, an inlet connected by a pipe to the compressed gas outlet of the compressor, and an outlet for the flow of compressed gas loaded with cryogenic beans,

- a coupling pipe (327) placed between an outlet of the sprayer and the inlet of the accelerator head.

16. Pickling system according to claim 14 or 15, characterized in that the accelerator head comprises a statoreactor.

17. Pickling system according to any one of the preceding claims, characterized in that the sprayer (320) comprises a die for the passage of compressed gas for transporting the grains and a die for the passage of a flow of fire gas the two channels joining after the cryogenic grains have been introduced into the compressed gas transport stream.

18. Pickling system according to claim 15, characterized in that the sprayer (320) comprises a reservoir of cryogenic particles, a device for forming cryogenic grains based on cryogenic particles and a device for adjusting the flow rate of the cryogenic grains introduced into the compressed gas transport stream.

19. Pickling system according to claim 15, characterized in that it comprises a reservoir of cryogenic particles, a reservoir of additive particles and a device for forming cryogenic grains based on cryogenic particles and particles of synthetic additive. or mineral, the latter being in a proportion of 1 to 5% of the total volume.

20. Pickling system according to claim 18, characterized in that the device for forming cryogenic grains with additive is integrated in a chamber forming the two particle reservoirs, the grains thus obtained consist of cryogenic particles and additive particles , mixed.

21 pickling system according to claim 18, characterized in that the reservoir of additive particles is placed downstream of the sprayer and is coupled to the outlet pipe of the sprayer, the grains obtained consist of an agglomerate of cryogenic particles on which adhere the additive particles introduced into the flow circulating in the pipe.

22. Pickling system according to any one of the preceding claims, characterized in that the • mobile unit (10) comprises a carriage provided with a telescopic arm (20) carrying a nacelle (30) in which is installed all or part of the propulsion device (300), a radio positioning device and sensors.

23. Pickling system according to any one of the preceding claims, characterized in that it further comprises a cockpit (40) of the carriage and real-time control of the pickling operation receiving the signals sent by the radio positioning device (70) and by the sensors (32, 33).

24. Pickling system according to any one of the preceding claims, characterized in that the radio positioning device provides the geographical coordinates of the projection head in real time, which makes it possible to obtain traceability of the pickling in space.