Device for the electrochemical surface treatment of an internal surface of a tubular element made of electroconductive material, in particular a weapon tube, and a system comprising such a device

Abstract

The invention relates to a device (D) and an electrochemical surface treatment system for an internal surface of a longitudinal tubular element (T) made of electroconductive material, which device (D) comprises: a chassis assembly (1); at least one cathode (2) configured to be electrically connected to the tubular element (T); a longitudinal anode configured to be placed coaxially inside the tubular element (T); means forming a sealed interface (4A, 4B) configured to cooperate removably with the tubular element (T) and with the anode, the means forming a sealed interface (4A, 4B) comprising at least first and second inlet / outlet ports intended to be connected to a source of treatment liquid and capable of communicating, in use, with a sealed longitudinal passage formed between the anode and the internal surface of the tubular element (T);and, means for rotating the tubular element (T) around its longitudinal axis (X0), characterized in that the frame assembly (1) is capable of supporting the tubular element (T) in a non-vertical orientation and that the device (D) further comprises means for tensing the anode configured to act on at least one of the two ends of the anode in order to prevent deflection of the anode. Figure to be published with the abbreviation: Figure 1.;

Description

Title of the invention: Device for the electrochemical surface treatment of an internal surface of a tubular element made of electroconductive material, in particular a weapon tube, and a system comprising such a device

[0001] The technical field of the invention is that of electrochemical surface treatment.

[0002] The present invention relates to a device and a system for the electrochemical surface treatment of an internal surface of a tubular component made of an electrically conductive material, in particular a weapon tube. It should be emphasized that the present invention can be applied to the surface treatment of any tubular mechanical part made of an electrically conductive material. The electrochemical surface treatment(s) implemented by the present invention may be, but are not limited to, electrolytic metallic coating, in particular electrolytic chromium (chrome plating) or nickel (nickel plating) deposition, or electrolytic polishing (electropolishing).

[0003] In the field of weaponry, which is one of the applications of the present invention, it is known to coat the inner wall of a gun barrel with a thin layer of chromium in order to improve the barrel's resistance to wear and friction during the passage of projectiles and, consequently, to increase the number of projectiles the barrel can fire during its service life. Indeed, chromium has high hardness and low chemical interaction with other metals; these two combined properties considerably limit wear on the parts. Chromating also has the advantage of adding a corrosion-resistant coating to the gun barrel, which increases its service life, particularly in humid environments.

[0004] This chromium layer is generally applied electrolytically. For this purpose, an anode is inserted coaxially into the weapon tube and along its entire length. A suitable electrolyte, such as a chromic acid bath, is then made to circulate in one direction within the weapon tube, between the anode and the inner wall of the weapon tube, while a voltage is applied to the anode and the weapon tube. The electric current flowing from the anode to the weapon tube via the electrolyte causes the deposition of a thin layer of chromium on the inner surface of the weapon tube.

[0005] Patent GB712314, published on 21 / 07 / 1954, discloses such a process for electrolytically chrome-plating the inner surface of a gun barrel, as well as an apparatus for carrying out this process. In order to obtain a uniform coating, the gun barrel is positioned vertically and is made to rotate around its longitudinal axis.

[0006] This solution is suitable for light or medium caliber weapon tubes. However, due to the vertical positioning of the weapon tube, this solution has drawbacks when applied to large caliber weapon tubes several meters long, as it requires a very significant height and suitable handling equipment.

[0007] The present invention thus aims to provide a solution enabling the electrochemical surface treatment, in particular electrolytic chrome plating, of the inner surface of a tubular element made of electroconductive material, in particular of a large caliber weapon tube, in a space having a reduced height volume, while ensuring a distribution of a metallic deposit that is as constant as possible in thickness in the case of a metallic coating.

[0008] The solution according to the present invention is based on the use of a device for orienting the tubular element in a non-vertical orientation, such as horizontally, and further comprising both means for tensile testing of the anode and means for rotating the tubular element about its longitudinal axis. The means for tensile testing of the anode make it possible to give the anode the greatest possible straightness and to maintain it strictly coaxial with the tubular element so that it remains equidistant from the inner wall of the tubular element, thus preventing its deflection. The means for axially rotating the tubular element prevent gases, particularly those resulting from electrolysis, from accumulating at a given point on the tubular element, a point which would then receive less metal deposit in the case of a metallic coating.Together, the means for tensing the anode and the means for driving the tubular element in axial rotation prevent the occurrence of a phenomenon of narrowing of the inner diameter of the tubular element, of the "hourglass effect", in which the metallic deposit has a profile comparable to that of an hourglass.

[0009] The solution according to the present invention also relies on the use of a system comprising such a device and further comprising means for alternating circulation capable of circulating a treatment solution through the tubular element in both directions, alternately. In the case of a metallic coating, the means for alternating circulation make it possible to obtain a metallic coating that has been deposited at the same rate of metal deposition along the entire length of the tubular element, even at both ends, and thus to prevent the deposition from occurring more rapidly at one end than at the other, which would lead to the inner surface of the tubular element taking on a blunderbuss-like shape.

[0010] The present invention therefore relates to a device for the electrochemical surface treatment of an internal surface of a longitudinal tubular element made of an electroconductive material, in particular for the electrolytic metallic coating of an internal wall of a weapon tube, the tubular element having a longitudinal axis and being open at first and second ends, which device comprises:

[0011] - a chassis assembly configured to support such a tubular element so as to allow the tubular element to rotate around its longitudinal axis;

[0012] - at least one cathode intended to be connected to the negative terminal of a current source and configured to be electrically connected to the tubular element;

[0013] - a longitudinal anode intended to be connected to the positive pole of the current source and configured to be placed inside the tubular element, coaxially with the longitudinal axis and at least along the entire length of the tubular element;

[0014] - means forming a watertight interface configured to cooperate in a removable with the tubular element at the first and second ends of the tubular element and to ensure the sealing of said first and second ends, and to cooperate with the anode to ensure its centering relative to the tubular element, the means forming a sealed interface comprising at least one first inlet / outlet port suitable for communicating with the first open end of the tubular element and at least one second inlet / outlet port suitable for communicating with the second open end of the tubular element, such that in use, a sealed longitudinal passage is formed between the anode and the inner surface of the tubular element from the first to the second end of the tubular element, the inlet / outlet ports being intended to be connected to a source of treatment liquid; and

[0015] - means for rotating the tubular element around its axis longitudinal,

[0016] characterized by the fact that the chassis assembly is capable of supporting the tubular element in a non-vertical orientation of the latter and that the device further comprises means for tensing the anode configured to, when the anode is mounted inside the tubular element, act on at least one of the two ends of the anode in order to prevent a bending of the anode.

[0017] Thanks to the presence of both anode tensioning means and axial rotation driving means for the tubular element, it can be seen that the occurrence of an "hourglass" effect can be avoided during a metal deposition operation using the device according to the invention. Furthermore, it turns out that the presence of anode tensioning means makes it possible, in use, to obtain a satisfactory surface treatment even when the tubular element is positioned horizontally on the assembly. chassis, even in the case of a long tubular element. It is then possible to use the device according to the invention in a workshop with limited vertical space.

[0018] The device according to the invention may be a chrome plating device, the source of treatment liquid then being a chrome plating bath, in particular a chromic acid bath.

[0019] Preferably, the anode comprises a cylindrical rod formed from a single piece of conductive metal, in particular copper, and at each end, a lead sleeve brazed to the rod. Such a lead sleeve improves the corrosion resistance of the anode and ensures sufficient mechanical strength over time.

[0020] Preferably, the rotation drive means include means for controlling the direction and / or speed of rotation.

[0021] In a particular embodiment, the means for rotating the tubular element are configured to produce an alternating rotational movement of the tubular element, so that in use, the tubular element is able to be rotated, over a determined angular range, alternately in a given direction of rotation, and then in the opposite direction of rotation.

[0022] Advantageously, the rotation drive means are configured to allow axial rotation movement in either of the two directions of rotation over a maximum angular range of 360 degrees, corresponding to one turn of the tubular element around its longitudinal axis.

[0023] In a particular embodiment, the rotational drive means comprise a rack and pinion system, the rack being coupled to a motor via a connecting rod and the pinion being coupled to a pulley-belt assembly, which pulley-belt assembly is connected to a roller assembly for supporting the tubular element and the rollers being mounted for rotation about axes parallel to the longitudinal axis of the tubular element. At least some of the rollers are driven in rotation by the pulley-belt assembly, so as to themselves rotate the tubular element.

[0024] Advantageously, the means for tensioning the anode are configured to allow tension adjustment by screwing the anode onto one of the means forming a sealing interface. Such tensioning of the anode, by mechanical tightening, is more reliable than tensioning by spring.

[0025] Preferably, in use, the tightening torque applied to put the anode into tension is on the order of 130 dN.m.

[0026] In a particular embodiment, the means for tensing the anode comprise at least one first tapped bore and at least one second tapped bore provided in the means forming a sealing interface, the first or one of the tapped bores being configured to cooperate with one end of the tubular element, in particular the second end, and the or one of the second tapped bores being configured to cooperate with an external thread provided on the corresponding end region of the anode, said first tapped bore having a reverse thread pitch relative to the thread pitch of said second tapped bore, such that in use, when said first tapped bore is screwed onto the end of the tubular element and the other end of the anode is held fixed, the end region of the anode bearing the external thread is caused to screw into said second tapped bore.

[0027] Advantageously, a reinforcing rod is provided for the removable attachment of the anode to the sealing interface means at the anode end region opposite the end region bearing the external thread. The rod has first and second external threads that cooperate, respectively, with a third tapped bore of the sealing interface means and an axial tapped orifice of the anode. Such a rod increases the strength at the attachment point.

[0028] Preferably, the axial tapped orifice is made in the first end region of the anode, and the external thread is provided on the second end region of the anode.

[0029] Advantageously, the means forming a sealing interface comprise, at the location of the first tapped bore(s), an external hexagonal profile made of electrically insulating material. Such a hexagonal profile is suitable for cooperating with a conventional tool, in particular a wrench capable of providing rotational locking or tightening, having a corresponding hexagonal profile.

[0030] In a particular embodiment, the means forming a watertight interface comprise a first and a second interface assembly, the first interface assembly comprising a first module of electrically insulating material configured to cooperate with the first end of the tubular element and to be traversed by the anode and a first module of electroconductive material fixed to the first module of electrically insulating material and configured to cooperate with the first end of the anode, the second interface assembly comprising a second module of electrically insulating material configured to cooperate with the second end of the tubular element and to be traversed by the anode and a second module of electroconductive material fixed to the second module of electrically insulating material and connected to the second end of the anode by means of the anode tensioning.

[0031] Preferably, each module made of electrically insulating material is made of PVDF (polyvinylidene fluoride) and each module made of electrically conductive material is Made of steel.

[0032] Preferably, a conical, sealed connection module made of an electrically insulating material and intended to be connected to a treatment liquid source is attached to each module made of an electrically conductive material. Each conical module has a converging orifice in communication with the inlet / outlet orifice(s) of the means forming a sealed interface. Such a conical module prevents turbulence and maintains laminar flow.

[0033] Preferably, at least one cathode is a peripheral cathode comprising a metal rod intended to be positioned outside the tubular element and along a generatrix thereof, the rod carrying at least one flange for connection to the tubular element and a connector module intended to connect the rod to the current source, the connector module being fixed to the means forming a watertight interface by being electrically isolated from the anode, such that in use, the tubular element takes the function of cathode.

[0034] Preferably, the modules are fixed to each other by removable fixing devices, in particular bolts.

[0035] In a particular embodiment, the chassis assembly comprises a supporting chassis and a movable chassis mounted on the supporting chassis and movable relative to the supporting chassis, at least pivoting about a pivot axis, the means for driving the rotation of the tubular element being fixed to the movable chassis, the amplitude of the pivoting of the movable chassis about the pivot axis allowing, in use, the tubular element to form an angle of inclination with respect to a horizontal plane between 0 and 90 degrees inclusive.

[0036] Preferably, at least one linear actuator is connected between the carrier chassis and the mobile chassis, one end of the actuator being articulated to the mobile chassis around an axis of rotation parallel to the pivot axis and eccentric with respect to the pivot axis.

[0037] Preferably, the carrier chassis is a rolling chassis, for example equipped with at least a first set of wheels and a second set of wheels.

[0038] The present invention also relates to a system for the electrochemical surface treatment of an internal surface of a tubular element made of electroconductive material, characterized in that it comprises a device as defined above, which system further comprises: - an electrical circuit comprising a current source whose positive pole is connected to the anode and whose negative pole is connected to at least one cathode; and - a hydraulic circuit connected to the first and second inlet / outlet ports of the device and comprising at least one source of treatment fluid and means for circulating the treatment fluid, which hydraulic circuit includes further means for alternating circulation suitable for circulating the treatment liquid in the longitudinal passage, first from the first to the second end, and then in a second step in the opposite direction from the second to the first end.

[0039] Thanks to the presence of both means for tensing the anode, means for driving the tubular element in axial rotation, and means for alternating circulation of a treatment liquid, it can be seen that the appearance of a "blunderbuss" phenomenon can be avoided during a metallic deposition operation implementing the system according to the invention.

[0040] The means for alternating circulation may include a reversible circulation pump driven by a drive motor capable of rotating in both directions of rotation.

[0041] Preferably, the anode is connected to the current source via a first conductive connecting element connected on one side to the positive pole of the current source and on the other side to the second module made of electroconductive material, and by the fact that the cathode is connected to the current source via a second conductive connecting element connected on one side to the negative pole of the current source and on the other side to the connector module.

[0042] Advantageously, the circulation speed of the treatment liquid is between 0.1 and 5 m / s and the applied current density is 20 to 60 A / dm2.

[0043] Preferably, the hydraulic circuit comprises a plurality of treatment liquid storage tanks, each tank being associated with at least one conduit for the delivery of the liquid it contains, which conduit is equipped with a solenoid valve, control means being provided to control the solenoid valves and to allow one of the storage tanks to be fluidly connected to the device.

[0044] Advantageously, the plurality of storage tanks includes at least one storage tank for acid attack solution and at least one storage tank for basic attack solution or liquid for carrying out a rinsing operation, at least one storage tank for chromium-based solution for carrying out a chromium plating operation, one storage tank for electropolishing solution and one storage tank for neutralization solution or liquid for removing hexavalent chromium.

[0045] To better illustrate the object of the present invention, a particular embodiment thereof will be described below, with reference to the accompanying drawings. In these drawings:

[0046] [Fig. 1] is a side view of the device according to a particular embodiment of the invention, a weapon tube being supported horizontally;

[0047] [Fig.2] is a perspective view of the device of [Fig.1], with brackets being added on either side of the supporting frame;

[0048] [Fig.3] is an enlarged perspective view of the rotational drive means, part of the chassis assembly and a section of the tube being omitted for clarity;

[0049] [Fig.4] is an enlarged perspective view of the device at the level of a first end of the tubular element;

[0050] [Fig.5] is a longitudinal sectional view of the enlarged region of [Fig.4];

[0051] [Fig.6] is an enlarged perspective view of the device at the level of a second end of the tubular element;

[0052] [Fig.7] is a longitudinal cross-sectional view of the enlarged region of [Fig.6]; and

[0053] [Fig.8] represents a diagram of the system according to the present invention.

[0054] If we refer first to Figures 1 to 7, we can see that the device D for The electrochemical surface treatment according to the present invention can be applied to the surface treatment of the inner wall Pi of a weapon tube T, particularly a rifled weapon tube. In the following description, the term "weapon tube" or "tube" is therefore used to designate the element to which the device D is applied. However, the application of the device D according to the invention is not limited to weapon tubes T; the element can be any longitudinal tubular element made of an electroconductive material, including a long tubular element.

[0055] As can be seen in Figures 1 and 2, the device D according to the invention comprises at least one chassis assembly 1, a cathode 2, an anode 3, means forming a watertight interface 4A, 4B, means for rotating the weapon tube T 5, and means for tensing the anode 3 6.

[0056] The chassis assembly 1 has the function of supporting the weapon tube T to be treated in a non-vertical orientation of the weapon tube T.

[0057] In the particular embodiment shown, the chassis assembly 1 comprises a support chassis 10 configured to support the tube T horizontally while allowing it to rotate about its longitudinal axis X0. To this end, the support chassis 10 carries the rotation drive means 5 for the tube T. The support chassis 10 is a welded steel frame on braked casters 11, comprising longitudinal beams connected by cross members. As can be seen in [Fig. 2], brackets 12 can be provided at each longitudinal end of the support chassis 10 to allow the suspension of electrical cables 9 and fluid lines 17 intended to be connected to the device D. Similarly, a pair of scopes 13 forming frames arranged in vertical planes and suitable for the passage of the gun tube T, can be mounted on the upper beams of the support chassis 10.The upper longitudinal members and the spectacles 13 are configured such that the longitudinal position of the spectacles 13 on the supporting frame 10 is adjustable, thus adapting to the length of the workpiece to be processed.

[0058] Alternatively, the chassis assembly 1 could also include a movable chassis (not shown) mounted on the carrier chassis 10 and carrying the rotation drive means 5 for the tube T. For example, the movable chassis could be mounted to pivot relative to the carrier chassis 10 about a horizontal pivot axis orthogonal to the longitudinal axis of the carrier chassis 10. The pivoting movement of the movable chassis about the pivot axis could be controlled by a jack connected to the carrier chassis 10 and articulated to the movable chassis about a rotation axis parallel to the pivot axis. Thus, in use, an extension of the jack rod causes the movable chassis, and therefore the weapon tube T it supports, to move to a higher position, for example, a position in which the longitudinal axis X0 of the weapon tube is horizontal.Conversely, retracting the cylinder rod causes the mobile frame, and therefore the weapon tube T, to move to a lower position in which the longitudinal axis X0 of the weapon tube T forms an angle between 0 and 90 degrees with respect to a horizontal plane. It should be noted that the cylinder could be replaced by any other suitable linear actuator. Thus, such a frame assembly allows the weapon tube T to be positioned at any desired angle of inclination. To ensure that the tube remains axially positioned relative to the mobile frame, particularly when the angle of inclination is significant, an anti-slip ring is mounted around the tube and butts against a stop element on the mobile frame.

[0059] The cathode 2, once connected to the negative (-) terminal of a current source 8, allows the gun tube T to function as a cathode. As can be seen in Figures 1, 2, 6, and 7, the cathode 2 comprises a metal rod 20 positioned along the outside of the tube T and connected to the tube T by electrically conductive connecting flanges 21 that fit around the tube T. The rod 20 is connected to the current source 8 via a connector module 22. This module 22, made of electrically conductive material, is fitted around an electrically insulating module 40A of the means forming a watertight interface 4A and around the rod 20. A conductive connecting element 23, connected to the negative (-) terminal of the current source 8, is received in the connector module 22.Thus, once the current source 8 is energized, the current flows in an electrical circuit CE to the connection element 23, then flows successively through the connector module 22, the rod 20, the flanges 21 and the wall of the T-tube.

[0060] The anode 3 is a longitudinal cylindrical part made of conductive metal, in particular copper and lead. As can be seen in Figures 5 and 7, in the assembled state, the anode 3 is centered coaxially with the gun tube T and protrudes on either side of the ends E1, E2 of the gun tube T. An annular channel is formed between the anode 3 and the inner wall surface P1 of the tube T, which channel defines a passage longitudinal 7 from one open end to the other of the T tube. Thus, the diameter of the anode 3 is a function of the surface treatment to be applied, for example, the desired thickness of metallic deposit, and the dimensions of the T tube.

[0061] As can be seen in [Fig. 5], the anode 3 is connected to the positive (+) terminal of a current source 8 via an electroconductive material module 41B of the means forming a watertight interface 4B. This module 41B receives a conductive connecting element 30 connected to the current source 8 and cooperates with an end region of the anode 3. In particular, this end region of the anode 3 has an external thread 31 which engages with a tapped bore 413 of the module 41B. Thus, once the current source 8 is energized, the current flows in an electrical circuit CE to the connecting element 30, then flows through the electroconductive module 41B and into the anode 3. As can be seen in [Fig. 7], the other end region of the anode 3 has a tapped axial orifice 32.A reinforcing rod 33 allows the anode 3 to be fixed, by its threaded end, to another electroconductive module 41A of the means forming a sealing interface 4A. This reinforcing rod 33 has threaded longitudinal end regions whose external threads engage, respectively, with a threaded bore 413 of the electroconductive module 41A and with the axial threaded orifice 32 of the anode 3.

[0062] The means forming a watertight interface 4A, 4B have the function of sealing the weapon tube T at each of its two open ends El, E2, of maintaining the anode 3 in position in the tube T and of allowing a fluidic connection between a source of treatment liquid Ci to Cn and the longitudinal passage 7 formed inside the tube T. The means forming a watertight interface 4A, 4B comprise first 4A and second 4B together forming an interface cooperating, respectively, with the first El and second E2 ends of the weapon tube T and the anode 3.

[0063] Referring to Figures 6 and 7, it can be seen that the first assembly forming interface 4A comprises a first module of electrical insulating material 40A, a first module of electroconductive material 41A and a first conical module 42A of watertight connection.

[0064] The first electrically insulating module 40A is a tubular body made, for example, of PVDF and having a hexagonal external profile section 401, a cylindrical section 402, and an annular section 403. The inner wall of the hexagonal external profile section 401 has internal threads 404 that cooperate with external threads T1 carried by the first end region El of the tube T. Thus, this insulating module 40A is fixed by screwing to the first end El of the tube T. The cylindrical section 402 is dimensioned such that the connector module 22 is fitted around it. The through-hole 405 of this insulating module 40A is arranged coaxially with the longitudinal axis X0 of the tube T and the anode 3 so as to open into the T tube. The annular section 403 has an outside diameter greater than the outside diameter of the cylindrical section 402, so as to allow the assembly of this module 40A with the first electroconductive module 41A by removable fixing elements, in particular bolts 43.

[0065] The first module made of electrically conductive material 41A is a tubular body, for example made of steel, having a cylindrical section 410 interposed in two annular sections 411. The cylindrical section 410 has a cylindrical orifice 412 into which the first end region of the anode 3 is placed. The cylindrical orifice 412 is coaxial with the longitudinal axis X0. This section 410 thus allows the positioning, in particular the centering, of the anode 3 relative to the tube T. The threaded bore 413, which engages with the reinforcing rod 33, opens into this cylindrical orifice 412. Thus, the anode 3 is fixed, by its first end, to the first electrically conductive module 41A. One of the annular sections 411 is in contact with the annular section 403 of the first insulating module 40A, the two modules 40A and 41A being assembled in a sealed manner.The other annular section 411 is in contact with an annular section 420 of the first conical module 42A, the two modules 41A, 42A also being hermetically sealed together by means of bolts 43, bushings and sealing gaskets. A plurality of cylindrical channels 414 are arranged around the orifice 412 coaxial with the gun tube T. These channels 414 open on one side into the through orifice 405 of the first insulating module 40A and on the other side into a converging orifice 423 of the first conical module 42A.

[0066] The first conical module 42A is a tubular body made of an electrically insulating material, in particular plastic, and having an annular section 420 for attachment to the first electroconductive module 41A, a conical section 421 and a cylindrical section 422. The converging orifice 423 is formed in the conical section 421. A cylindrical inlet / outlet orifice 424 is formed in the cylindrical section 422. The converging orifice 423 opens into the cylindrical inlet / outlet orifice 424. Thus, a liquid from a treatment liquid source Ci to Cn can flow successively through the inlet / outlet orifice 424, the converging orifice 423, the plurality of channels 414, the through orifice 405 and the longitudinal passage 7 between the anode 3 and the tube T.

[0067] Referring to Figures 4 and 5, it can be seen that the second assembly forming interface 4B comprises a second module of electrical insulating material 40B, a second module of electroconductive material 41B and a second conical module 42B of watertight connection.

[0068] The second insulating module 40B is analogous to the first insulating module 40A and is screwed to the second end E2 of the tube T. In particular, the internal threads 404 provided in the hexagonal external profile section 401, and designated by first tapped bore, cooperate with the external threads T2 of the second end region E2 of the T tube.

[0069] The second module made of electroconductive material 41B is analogous to the first electroconductive module 41A, except that it has a radial orifice 415 in the annular section 411 in contact with the annular section 403. This orifice 415 is configured to receive the connecting element 30 for the electrical connection of the anode 3 to the current source 8. The second end region of the anode 3 passes through the cylindrical orifice 412 and the tapped bore 413, the external thread 31 of the anode 3 engaging with the thread of the tapped bore 413, designated as the second tapped bore. The thread pitch of this second tapped bore 413 is reversed with respect to the thread pitch of the first tapped bore 404.Thus, when positioning the anode 3 relative to the tube T, the first end of the anode 3 being held fixed against rotation by the rotational block at the hexagonal profile section 401, screwing the second insulating module 40B along the second end E2 of the weapon tube T causes the second end of the anode 3 to be screwed into the second electroconductive module 41B, therefore opposite the first end of the anode 3. The threaded bores 404, 413 of the means forming a watertight interface 4A, 4B therefore constitute the means of tensile tightening of the anode 3.

[0070] The second conical module 42B is analogous to the first conical module 42A.

[0071] The rotation drive means 5 of the weapon tube T are designed to allow axial rotation of the tube T, in other words, rotation of the tube T around its longitudinal axis X0. In the preferred embodiment of the invention, these means 5 allow the tube T to perform an axial rotation of 360 degrees in a first direction of rotation and then an axial rotation of 360 degrees in a second opposite direction of rotation, alternately.

[0072] As can be seen in [Fig. 3], these drive means 5 may include a control means, in particular a motor 50 carried by the upper longitudinal members of the chassis assembly 1, and transmission means. The transmission means include a connecting rod 51 coupled to the output shaft of the motor 50 and connected to a rack 52 of a rack and pinion system. Thus, a rotation of the motor 50 causes a translational displacement of the rack 52 alternately in a first direction and in a second direction. The translational displacement of the rack 52 then causes the associated pinion 53 to rotate in one direction or the other. This pinion 53 is coupled to a pulley-belt assembly, one of the pulleys 54 of which is mounted on a shaft coupled to the pinion 53, and the other pulley 55 of which is mounted on a first shaft of a roller assembly 57.Thus, the rotation of the pinion 53 causes the rotation of the pulleys 54, 55, via the belt 56, and therefore the rotation of the first shaft carrying the roller assembly 57. The assembly. The roller assembly 57 comprises a first pair of rollers mounted on the first shaft and a second pair of rollers mounted on a second shaft, the second shaft being coupled to the first shaft by another pulley-belt assembly 58. The first and second shafts are parallel to each other and parallel to the longitudinal axis XO. The two pairs of rollers 57 are arranged on either side of the longitudinal axis XO and below the gun tube T so as to support the tube T from below and to transmit the rotational movement of the rollers 57 to the gun tube T. The roller assembly 57 is supported by upper longitudinal members of the chassis assembly 1, at one of the longitudinal end regions of the chassis assembly 1. At the other longitudinal end region of the chassis assembly 1, a pair of rollers 59 are provided, mounted freely to rotate about axes of rotation parallel to each other and parallel to the longitudinal axis XO.These rollers 59 support the weapon tube T via a bearing ring assembly 60, which allows, if necessary, compensation for any conicity of the weapon tube T. The bearing ring assembly 60 is mounted around the weapon tube T and is traversed by the rod 20 of the cathode 2. Thus, the assembly comprising the weapon tube T, the cathode 2, the anode 3 and the means forming a watertight interface 4A, 4B is able to rotate when the weapon tube T is rotated around its longitudinal axis XO.

[0073] Referring now to [Fig. 8], it can be seen that for the implementation of a surface treatment, the device D according to the present invention is integrated into a surface treatment system S, in particular a closed-circuit system. The system S according to the present invention comprises an electrical circuit CE and a hydraulic circuit CH connected to the device D described above.

[0074] The electrical circuit CE includes a current source 8 and electrical cables 9 connecting, on the one hand, the positive pole (+) of the current source 8 and the anode 3 by passing the current through the connection element 30 received in the second electroconductive module 41B, and on the other hand, the negative pole (-) of the current source 8 and the cathode 2 by passing the current through the connection element 23 received in the connector module 22.

[0075] The hydraulic circuit CH comprises a plurality of process fluid storage tanks Ci to Cn, constituting at least one source of process fluid. Each tank Ci to Cn is associated with at least one upstream conduit 14 equipped with a solenoid valve 15, which is connected to control means 16, including a human-machine interface, a programmable logic controller (PLC) with probes, and sensors. Process fluid circulation means, such as pumps, allow the fluid to be circulated through the upstream conduits 14. Downstream conduits 17 connected to the upstream conduits 14 are in fluidic communication with the inlet / outlet ports 424 of the first 42A and second 42B conical modules to allow circulation of a treatment liquid between one of the tanks Ci to Cn and the longitudinal passage 7. The circulation of the liquid in the downstream conduits 17 is controlled by alternating circulation means 18 adapted to circulate one of the treatment liquids through the longitudinal passage 7 alternately in a first direction of circulation and in a second direction of circulation (double-direction arrows in [Fig. 8]). Thus, treatment liquid enters the passage 7 through the first end El of the tube T and exits the passage 7 through the second end E2 of the tube T, then after a certain predetermined time, treatment liquid enters the passage 7 through the second end E2 of the tube T and exits the passage through the first end El of the tube T. In [Fig. 8], the alternating circulation means 18 are schematically represented by a reversible circulation pump driven by a drive motor adapted to rotate in both directions.

[0076] In operation, the method implementing system S according to the invention comprises the following preliminary steps:

[0077] - mounting the cathode 2 onto the weapon tube T via the two flanges connection 21;

[0078] - the mounting of the bearing ring assembly 60 around the T-tube and the cathode 2;

[0079] - the mounting of the connector module 22 around the first insulating module 40A;

[0080] - the fixing of the first 40A insulating module on the first end El of the T-tube and the fixing of the second insulating module 40B on the second end E2 of the tube T. For this, for each insulating module 40A, 40B, a key corresponding to the hexagonal profile 401 is used to screw the module 40A, 40B onto the threads Tl, T2;

[0081] - the attachment of the second electroconductive module 41B to the second insulating module 40B;

[0082] - the introduction of the anode 3 inside the tube T by introducing the anode 3 from the first insulating module 40A, until the threads 31 of the second end of the anode 3 cooperate with the tapped bore 413 of the second electroconductive module 41B;

[0083] - the attachment of the first electroconductive module 41A to the first end of the anode 3 by screwing the reinforcing rod 33 into the tapped bore 413, then fixing the first electroconductive module 41A to the first insulating module 40A;

[0084] - the tensile activation of anode 3. For this, a first operator maintains in Position the first insulating module 40A relative to the T-tube using a wrench corresponding to the hexagonal profile 401, so that the first insulating module 40A, and therefore the first electroconductive module 41A and the anode 3, are prevented from rotating. A second operator screws the second insulating module 40B onto the T-tube using a corresponding wrench and applies a tightening torque, specifically 130 dN.m. due to the reverse threads of the tapped bores 404, 413, this screwing allows the anode 3 to be put under tension between the two electroconductive modules 41A, 41B;

[0085] - the mounting of the weapon tube T on the rotating drive means 5 supported by the chassis assembly 1. For this, the bearing ring assembly 60 is placed on the pair of rollers 59 mounted freely in rotation and a region of the tube T located between the cathode 2 and the second assembly forming interface 4B is placed on the pairs of rollers 57 driven in rotation by the motor 50;

[0086] - the fixing of the first and second conical modules 42A, 42B to the first and second electroconductive modules 41A, 41B, respectively;

[0087] - if necessary, particularly in the case of a long T-tube, the mounting of gantries 12 on the carrier frame 10 and the suspension of electrical cables 9 and hydraulic pipes 17 to these gantries 12.

[0088] Once these preliminary steps have been carried out, the tube T to be treated is ready to form a cathode and is positioned in the desired non-vertical position, in particular horizontally, and the anode 3 is kept strictly coaxial with the longitudinal axis X0 of the tube T.

[0089] The electrochemical treatment process may then comprise the following treatment steps:

[0090] - the connection of the conical modules 42A, 42B to the hydraulic circuit CH;

[0091] - the connection of the current source 8 to the cathode 2 by means of the module assembly connector 22 around the first insulating module 40A and around the rod 20 and the connection of the connecting element 23 to the negative pole (-), and to the anode 3 by the connection of the connecting element 30 of the second electroconductive module 41B to the positive pole (+);

[0092] - the introduction of an electrolyte into the longitudinal passage 7 by actuation of the means of circulation and control of piloting means 16;

[0093] - once the temperature of the surface of tube T has been homogenized, the power-up from the current source 8. The passage of an electric current in the treatment liquid flowing in the longitudinal passage 7 allowing the surface treatment of the inner wall Pi of the tube T;

[0094] - during surface treatment, the actuation of the circulation means alternating 18 of the treatment liquid and the means of rotating tube 5. Thus, the tube T is made to pivot around its longitudinal axis X0, in alternating directions of rotation and the treatment liquid passes through the tube T in one longitudinal direction, then in the other.

[0095] Once the surface treatment is completed, the circulation of the treatment liquid is stopped, the tube T is drained, the interface assemblies 4A, 4B are disassembled and the device D is disconnected from the electrical circuit CE and the hydraulic circuit CH.

[0096] It is therefore understood that the system S according to the present invention allows for the implementation of a sequence of surface treatments. For example, the system S can perform cleaning of the inner surface of the tube T to prepare for the subsequent adhesion of a coating, electrolytic chrome plating to deposit a layer of chrome, one or more rinses, electropolishing, etc., depending on the desired treatment. The control means 16 of the hydraulic circuit CH control the fluid connection between the tank Ci to Cn containing the appropriate treatment liquid and the device D. For example, for cleaning, the device D according to the invention is traversed by an etching liquid (acid, base, etc.), whereas for chrome plating, the device D is traversed by a chromium-based liquid. Thus, the number of storage tanks Ci to Cn and the treatment liquids contained in these tanks are adapted to the desired surface treatments.Furthermore, current flows through the electrical circuit only when the treatment to be carried out is electrochemical.

[0097] It is understood that the particular embodiments which have just been described have been given by way of indication and not limitation, and that modifications may be made without departing from the scope of the present invention.

Claims

Demands

1. Device (D) for the electrochemical surface treatment of an inner surface of a longitudinal tubular element (T) made of electrically conductive material, in particular for the electrolytic metallic coating of an inner wall (Pi) of a weapon tube (T), the tubular element (T) having a longitudinal axis (XO) and being open at first and second ends (E1, E2), which device (D) comprises: - a chassis assembly (1) configured to support such a tubular element (T) in such a way as to allow the tubular element (T) to rotate around its longitudinal axis (XO); - at least one cathode (2) intended to be connected to the negative pole of a current source (8) and configured to be electrically connected to the tubular element (T); - a longitudinal anode (3) intended to be connected to the positive pole of the current source (8) and configured to be placed inside the tubular element (T), coaxially to the longitudinal axis (XO) and at least along the entire length of the tubular element (T); - means forming a watertight interface (4A, 4B) configured to cooperate removably with the tubular element (T) at the first (El) and second (E2) ends of the tubular element (T) and to ensure the sealing of said first and second ends (El, E2), and to cooperate with the anode (3) in order to ensure its centering with respect to the tubular element (T), the means forming a watertight interface (4A, 4B) comprising at least one first inlet and outlet orifice (424) adapted to communicate with the first open end (El) of the tubular element (T) and at least one second inlet and outlet orifice (424) adapted to communicate with the second open end (E2) of the tubular element (T), such that in use, a watertight longitudinal passage (7) is formed between the anode (3) and the inner surface of the tubular element (T) from the first (El) to the second (E2) end of the tubular element (T),the inlet and outlet ports (424) being intended to be connected to a source of treatment fluid (C i-Cn); and, - means for rotating the tubular element (T) around its longitudinal axis (XO), characterized by the fact that the chassis assembly (1) is capable of supporting

2.

3.

4. the tubular element (T) in a non-vertical orientation of the latter and that the device (D) further comprises means for tensile testing (6) of the anode (3) configured to, when the anode (3) is mounted inside the tubular element (T), act on at least one of the two ends of the anode (3) in order to prevent a bending of the anode (3). Device (D) according to claim 1, characterized in that the means for tensioning (6) of the anode (3) are configured to allow tension adjustment by screwing the anode (3) onto one of the means forming a sealed interface (4A, 4B). Device (D) according to any one of claims 1 and 2, characterized in that the anode tensioning means (6) comprise at least one first tapped bore (404) and at least one second tapped bore (413) provided in the sealing interface means (4A, 4B), the first tapped bore(s) (404) being configured to cooperate with one of the ends (E1, E2) of the tubular element (T), in particular the second end (E2), and the second tapped bore(s) (413) being configured to cooperate with an external thread (31) provided on the corresponding end region of the anode (3), said first tapped bore (404) having a reverse thread pitch relative to the thread pitch of said second tapped bore (413), such that in use, when said first tapped bore (404) is screwed onto the end of the tubular element (T) and the other end of the anode (3) is held fixed,the end region of the anode (3) carrying the external thread (31) is made to screw into said second tapped bore (413).

4. Device (D) according to any one of claims 1 to 3, characterized in that the means forming a watertight interface (4A, 4B) comprise a first (4A) and a second (4B) interface assembly, the first interface assembly (4A) comprising a first module of electrically insulating material (40A) configured to cooperate with the first end (E1) of the tubular element (T) and to be traversed by the anode (3) and a first module of electroconductive material (41A) fixed to the first module of electrically insulating material (40A) and configured to cooperate with the first end of the anode (3), the second interface assembly (4B) comprising a second module of electrically insulating material (40B) configured to cooperate with the second end (E2) of the tubular element (T) and to be traversed by by 1 anode (3) and a second module of electroconductive material (41B) fixed to the second module of electrical insulating material (40B) and connected to the second end of the anode (3) by means of the anode tensioning means (6).

5. 5 Device (D) according to any one of claims 1 to 4, characterized in that at least one cathode (2) is a peripheral cathode comprising a metal rod (20) intended to be positioned outside the tubular element (T) and along a generatrix thereof, the rod (20) carrying at least one connection flange (21) to the tubular element (T) and a connector module (22) intended to connect the rod to (20) the current source (8), the connector module (22) being fixed to the means forming a watertight interface (4A, 4B) by being electrically isolated from the anode (3), such that in use, the tubular element (T) takes the function of a cathode.

6. Device (D) according to any one of claims 1 to 5, characterized in that the chassis assembly (1) comprises a supporting chassis (10) and a movable chassis mounted on the supporting chassis (10) and movable relative to the supporting chassis (10), at least pivoting about a pivot axis, the means for rotating (5) the tubular element (T) being fixed to the movable chassis, the amplitude of the pivoting of the movable chassis about the pivot axis allowing, in use, the tubular element (T) to form an angle of inclination with respect to a horizontal plane between 0 and 90 degrees inclusive.

7. Device (D) according to any one of claims 1 to 6, characterized in that the means for rotating the tubular element (T) are configured to produce an alternating rotational movement of the tubular element (T), so that in use, the tubular element (T) is able to be rotated, over a determined angular range, alternately in a given direction of rotation, and then in the opposite direction of rotation.

8. System (S) for the electrochemical surface treatment of an internal surface of a tubular element (T) made of electroconductive material, characterized in that it comprises a device (D) according to any one of claims 1 to 7, which system (S) further comprises: an electrical circuit (EC) including a current source (8) whose positive pole is connected to the anode (3) and whose negative pole is connected to at least one cathode (2); and - a hydraulic circuit (CH) connected to the first and second inlet and outlet ports (424) of the device (D) and comprising at least one source of treatment liquid (Ci -Cn) and means for circulating treatment liquid, which hydraulic circuit (CH) further comprises means for alternating circulation (18) suitable for circulating the treatment liquid in the longitudinal passage (7), initially from the first (E1) to the second (E2) end, and then in a second time in the opposite direction from the second (E2) to the first (E1) end.

9. System (S) according to claim 8, characterized in that the anode (3) is connected to the current source (8) via a first conductive connecting element (30) connected on one side to the positive pole of the current source (8) and on the other side to the second module made of electroconductive material (41A; 41B), and in that the cathode (2) is connected to the current source (8) via a second conductive connecting element (23) connected on one side to the negative pole of the current source (8) and on the other side to the connector module (22).

10. System (S) according to any one of claims 8 and 9, characterized in that the hydraulic circuit (CH) comprises a plurality of processing liquid storage tanks (Ci-Cn), each tank (Ci-Cn) being associated with at least one conduit (14) for the delivery of the liquid it contains, which conduit (14) is equipped with a solenoid valve (15), control means (16) being provided to control the solenoid valves (15) and to allow one of the storage tanks (Ci-Cn) to be fluidly connected to the device (D).

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