Device for electrochemical surface treatment of inner surface of tubular member made of electrically conductive material, in particular of gun barrel, and system comprising such device

Abstract

The invention relates to a device (D) and a system for the electrochemical surface treatment of the inner surface of a longitudinal tubular member (T) made of an electrically conductive material, the device (D) comprising: a frame assembly (1); at least one cathode (2) configured to be electrically connected to the tubular member (T); a longitudinal anode (3) configured to be coaxially arranged inside the tubular member (T); a sealed interface mechanism (4A, 4B) configured to removably mate with the tubular member (T) and the anode (3), said sealed interface mechanism (4A, 4B) comprising at least first and second inlet / outlet ends for connecting a source of treatment fluid and adapted, in use, to communicate with a sealed longitudinal passage (7) formed between the anode (3) and the inner surface of the tubular member (T); and a mechanism (5) for driving the tubular member (T) in rotation about the longitudinal axis (X0); characterised in that said frame assembly (1) is adapted to support the tubular member (T) in a non-vertical orientation, and in that the device (D) further comprises means for pulling the anode under traction configured to act on at least one of the two ends of the anode (3) to prevent it from flexing.

Description

Technical Field

[0001] The technical field of the present invention relates to the field of electrochemical surface treatment.

[0002] The present invention relates to a device and a system for the electrochemical surface treatment of the inner surface of a tubular member made of a conductive material, particularly a gun barrel. It should be particularly noted that the present invention is applicable to the surface treatment of any tubular mechanical part made of a conductive material. The electrochemical surface treatment achieved by the present invention can be an electrolytic metal coating, including but not limited to electrolytic chromium (chrome plating) or electrolytic nickel (nickel plating) or electrolytic polishing (electropolishing). Background Art

[0003] In the ordnance field (as one of the application fields of the present invention), it is known to improve the wear resistance and anti-friction properties of a gun barrel when a projectile passes through by plating a thin layer of chromium on the inner wall of the gun barrel, thereby increasing the number of projectiles that can be fired within the service life of the gun barrel. In fact, chromium has the characteristics of high hardness and low chemical interaction with other metals, and these two characteristics can significantly reduce component wear. The chromium plating process can also provide a corrosion-resistant coating for the gun barrel, especially in a humid environment, which can effectively extend the service life of the gun barrel.

[0004] This chromium layer is usually deposited by electrolysis. For this purpose, the anode is coaxially inserted into the gun barrel and extends along the entire length of the gun barrel. A suitable electrolyte, such as a chromic acid solution, is circulated through the gun barrel in a single direction between the anode and the inner wall of the gun barrel, while a voltage is applied between the anode and the gun barrel. The current flows from the anode to the gun barrel through the electrolyte, thereby depositing a thin layer of chromium on the inner surface of the gun barrel.

[0005] Patent GB712314, which was published on July 21, 1954, discloses a process for electroplating chromium on the inner surface of a gun barrel and a device for implementing this process. To obtain a uniform deposition layer, this technical solution positions the gun barrel vertically and rotates it around its longitudinal axis.

[0006] This solution is applicable to medium and small caliber gun barrels. However, for large caliber gun barrels several meters long, there are obvious defects in using such a vertical positioning method because it requires a large amount of vertical space and special lifting equipment. Summary of the Invention

[0007] The present invention aims to provide a solution for the electrochemical surface treatment, particularly electrolytic chromium plating, of the inner surface of a tubular member made of a conductive material, especially applicable to large caliber gun barrels, which can be implemented in a space with limited height and ensure that the thickness distribution of the metal coating is as uniform as possible.

[0008] The solution provided by the present invention is based on a device in which the orientation of a tubular member is in a non-vertical orientation, such as a horizontal orientation. The device simultaneously includes a mechanism for pulling the anode and a mechanism for driving the tubular member to rotate about its longitudinal axis. The mechanism for pulling the anode keeps the anode to be produced as straight as possible and strictly coaxial with the tubular member, thereby ensuring that the anode is equidistantly distributed from the inner wall of the tubular member to prevent skewing. The mechanism for driving the axial rotation of the tubular member prevents the accumulation of gas, especially electrolytic gas, at specific positions of the tubular member, where less metal deposition of the metal coating is obtained. At the same time, the mechanism for pulling the anode and the mechanism for driving the axial rotation of the tubular member prevent the inner diameter of the tubular member from shrinking, i.e., the "hourglass effect", which is manifested as an hourglass-shaped distribution profile of the metal deposition).

[0009] The solution of the present invention also relates to the use of a system that includes the device and further includes an alternating circulation mechanism that can bidirectionally circulate the treatment solution in the tubular member in an alternating manner. For a metal coating, the alternating circulation mechanism can deposit the final metal coating at the same metal deposition rate throughout the entire length of the tubular member, even at both ends, thereby avoiding the formation of a flared deformation on the inner surface of the tubular member due to too fast deposition rate at one end.

[0010] The present invention thus relates to a device for electrochemically surface-treating the inner surface of a longitudinally tubular member of a conductive material, particularly suitable for electrolytic metal coating of the inner wall of a gun barrel. The tubular member has a longitudinal axis and is provided with first and second open ends. The device includes:

[0011] - A frame assembly for supporting such a tubular member and enabling the tubular member to rotate about its longitudinal axis;

[0012] - At least one cathode connected to the negative pole of a current source and electrically connected to the tubular member;

[0013] - A longitudinal anode connected to the positive pole of a current source, disposed inside the tubular member and extending coaxially with the longitudinal axis and covering at least the entire length of the tubular member;

[0014] - A sealing interface mechanism detachably assembled with the tubular member at the first and second ends of the tubular member, sealing the first and second ends, and cooperating with the anode to ensure its centering positioning relative to the tubular member. The sealing interface mechanism includes at least one first inlet end and a first outlet end (or "inlet / outlet end") adapted to communicate with the first open end of the tubular member, and at least one second inlet end and a second outlet end (or "inlet / outlet end") adapted to communicate with the second open end of the tubular member, thereby forming a sealed longitudinal channel between the anode and the inner surface of the tubular member from the first end to the second end of the tubular member during use. The inlet end and the outlet end are connected to a treatment liquid source; and

[0015] - A mechanism for driving a tubular member to rotate about its longitudinal axis;

[0016] Characterized in that: the frame assembly is adapted to support the tubular member in a non-vertical direction, and the device further includes a mechanism for pulling the anode, configured such that when the anode is installed inside the tubular member, the mechanism acts on at least one of the two ends of the anode to prevent the anode from flexing.

[0017] By providing a mechanism for pulling the anode and a mechanism for driving the axial rotation of the tubular member, the device according to the present invention can effectively avoid the "hourglass effect" during the metal deposition operation. In addition, the presence of the mechanism for pulling the anode enables the tubular member to obtain an ideal surface treatment effect even when installed in the horizontal orientation on the frame assembly and even when the length of the tubular member is very long. Therefore, the device according to the present invention can be implemented in a workshop environment with limited height.

[0018] The device according to the present invention can be specifically implemented as a chromium plating device, in which case the treatment liquid source is chromium plating electrolyte, especially chromic acid electrolyte.

[0019] Preferably, the anode comprises a cylindrical rod made of a single piece of conductive metal, especially copper, with lead sleeves welded to both ends thereof. The lead sleeves can enhance the corrosion resistance of the anode and maintain sufficient mechanical strength for a long time.

[0020] Preferably, the mechanism for driving rotation includes means for controlling the rotation direction and / or rotation speed.

[0021] In a specific embodiment, the mechanism for driving the rotation of the tubular member is configured to produce an alternating rotational movement of the tubular member such that in use, the tubular member can rotate alternately in a given rotational direction and then in the opposite rotational direction within a given angular range.

[0022] Preferably, the mechanism for driving rotation is configured to allow the tubular member to perform an axial rotational movement of up to 360 degrees about its longitudinal axis in two rotational directions, corresponding to one full rotation of the tubular member about its longitudinal axis.

[0023] In a specific embodiment, the mechanism for driving rotation includes a rack and pinion system, where the rack is coupled to a motor through a connecting rod, and the pinion is coupled to a pulley belt assembly; the pulley belt assembly is connected to a roller assembly for supporting the tubular member, and the rollers of the roller assembly can rotate about an axis parallel to the longitudinal axis of the tubular member. At least some of the rollers are driven to rotate by the pulley belt assembly, thereby driving the tubular member to rotate.

[0024] Preferably, the mechanism for subjecting the anode to traction is configured to adjust the traction force by screwing the anode onto one of the sealing interface mechanisms. This method of subjecting the anode to traction through mechanical traction is more reliable than using a spring to subject the anode to traction.

[0025] Preferably, in the operating state, the tightening torque applied to subject the anode to traction is approximately 130 decinewton - meters.

[0026] In a particular embodiment, the mechanism for subjecting the anode to traction includes at least one first threaded hole and at least one second threaded hole provided on the sealing interface mechanism. One or the first threaded hole is for mating with one end of the tubular member, particularly the second end, and one or the second threaded hole is for mating with the external thread of the corresponding end region of the anode; the pitch of the first threaded hole is opposite to the pitch of the second threaded hole, so that in use, when the first threaded hole is screwed onto the end of the tubular member and the other end of the anode remains fixed, the end region of the anode with external threads will be screwed into the second threaded hole.

[0027] Preferably, a reinforcing rod is provided for detachably fixing the anode to the sealing interface mechanism. The rod is located in the end region opposite to the end region of the anode where the external thread is provided; the rod has a first external thread and a second external thread, which respectively cooperate with the third threaded hole of the sealing interface mechanism and the axial threaded hole of the anode. This rod can increase the strength of the fixing region.

[0028] Preferably, the axial threaded hole is provided in the first end region of the anode, and the external thread is provided in the second end region of the anode.

[0029] Preferably, the sealing interface mechanism includes an external hexagonal structure made of an electrically insulating material at the level of the or each first threaded hole. This hexagonal structure is adapted to cooperate with a conventional tool having a corresponding hexagonal profile, particularly a wrench suitable for rotational locking or tightening.

[0030] In a particular embodiment, the sealing interface mechanism includes a first interface component and a second interface component. The first interface component includes a first module made of an electrically insulating material for mating with the first end of the tubular member and penetrated by the anode, and a first module made of a conductive material fixed to the first module of the electrically insulating material and configured to mate with the first end of the anode. The second interface component includes a second module made of an electrically insulating material for mating with the second end of the tubular member and penetrated by the anode, and a second module made of a conductive material fixed to the second module of the electrically insulating material and connected to the second end of the anode through the mechanism for subjecting the anode to traction.

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

[0032] Preferably, a conical sealing connection module made of an electrically insulating material is fixedly attached to each module made of a conductive material. This conical module is used to connect to a treatment liquid source. Each conical module has a converging channel that communicates with the inlet / outlet end of the sealing interface mechanism. This conical structure prevents turbulence and maintains a laminar flow state.

[0033] Preferably, the at least one cathode is an outer peripheral cathode and includes a metal rod that is disposed outside the tubular member and arranged along its generatrix; the rod is provided with at least one flange for connecting the tubular member and a connection module for connecting the rod to a current source; the connection module is fixed to the sealing interface mechanism and is electrically isolated from the anode, so that the tubular member functions as a cathode during use.

[0034] Preferably, the modules are fixed to each other by detachable fasteners, in particular bolts.

[0035] In a specific embodiment, the frame assembly includes a support frame and a movable frame. The movable frame is mounted on the support frame and is movable relative to the support frame, at least capable of pivoting about a pivot axis; the mechanism for driving the rotation of the tubular member is fixed to the movable frame, and the pivoting amplitude of the movable frame about the pivot axis can make the tubular member in an inclined angle relative to the horizontal plane during use, where the inclined angle includes a range from 0 to 90 degrees (inclusive).

[0036] Preferably, at least one linear cylinder type actuator is connected between the support frame and the movable frame. One end of the actuator is hinged to the movable frame around a rotation axis that is parallel to the pivot axis and eccentrically disposed relative to the pivot axis.

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

[0038] The present invention also relates to a system for electrochemical surface treatment of the inner surface of a tubular member made of a conductive material, characterized by including the device defined above. The system further includes:

[0039] - An electrical circuit including a current source, whose positive pole is connected to the anode and whose negative pole is connected to the at least one cathode;

[0040] - A hydraulic circuit connected to the first and second inlet ends and the first and second outlet ends of the device and including at least one treatment liquid source and a device for circulating the treatment liquid. The hydraulic circuit further includes an alternating circulation mechanism that can make the treatment liquid flow back and forth in the longitudinal channel from the first end to the second end direction in the first step and then in the reverse direction from the second end to the first end direction in the second step.

[0041] By providing a mechanism for pulling the anode, a mechanism for axially rotating the tubular member, and a mechanism for alternately circulating the processing liquid, the system of the present invention can effectively avoid the "flare" phenomenon during the metal deposition operation.

[0042] The alternating circulation mechanism may include a reversible circulation pump driven by a bidirectional rotation drive motor.

[0043] Preferably, the anode is connected to a current source through a first conductive connection element, which is connected to the positive pole of the current source on one hand and to the second module of the conductive material on the other hand, and the cathode is connected to the current source through a second conductive connection element, which is connected to the negative pole of the current source on one hand and to the connection module on the other hand.

[0044] Preferably, the circulation speed of the processing liquid is 0.1 to 5 m / s, and the applied current density is 20 to 60 A / dm².

[0045] Preferably, the hydraulic circuit includes a plurality of processing liquid storage tanks, each tank being in communication with at least one pipeline for conveying the liquid it contains. The pipeline is provided with a solenoid valve and a control device for controlling the solenoid valve to achieve fluid communication between one of the storage tanks and the device.

[0046] Preferably, the plurality of storage tanks include: at least one acidic etching solution or liquid storage tank, at least one alkaline etching solution or liquid storage tank for performing a rinsing operation, at least one chromium-based solution storage tank for performing a chromium plating operation, an electrolytic polishing solution storage tank, and a neutralization solution or liquid storage tank for removing hexavalent chromium. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] To better illustrate the technical solution of the present invention, specific embodiments will be described below in conjunction with the drawings. The drawings are described as follows:

[0048] Figure 1 is a side view of the device in a specific embodiment of the present invention, showing a horizontally supported barrel;

[0049] Figure 2 is Figure 1 a perspective view of the shown device, with brackets added on both sides of the support frame;

[0050] Figure 3 is a partially enlarged perspective view of the mechanism for driving rotation, with some frame components and barrel segments omitted for clear display;

[0051] Figure 4 is an enlarged perspective view of the device at the first end of the tubular member;

[0052] Figure 5 is Figure 4Longitudinal sectional view of the enlarged area shown;

[0053] Figure 6 Is an enlarged perspective view of the device at the second end of the tubular member;

[0054] Figure 7 Is Figure 6 Longitudinal sectional view of the enlarged area shown; and

[0055] Figure 8 Shows a schematic diagram of the system of the present invention. Detailed implementation mode

[0056] First, referring to Figures 1 to 7 , it can be seen that the electrochemical surface treatment device D of the present invention is applicable to the barrel T, especially for the surface treatment of the inner wall Pi of the rifled barrel. In the following description, the term "barrel" or "tube body" refers to the object of action of the device D. However, the application scope of the device D of the present invention is not limited to the barrel T, and its object can be any longitudinally tubular member made of conductive material, including long tubular members.

[0057] As Figure 1 And Figure 2 Shown, the device D of the present invention includes at least one frame assembly 1, a cathode 2, an anode 3, sealing interface mechanisms 4A and 4B, a mechanism 5 for driving the barrel T to rotate, and a mechanism 6 for pulling the anode 3.

[0058] The function of the frame assembly 1 is to support the barrel T to be processed in a non-vertical direction of the barrel T.

[0059] In the specific embodiment shown, the frame assembly 1 includes a support frame 10, which is configured to horizontally support the barrel T and enable it to rotate around its longitudinal axis X0. For this purpose, the support frame 10 is equipped with a mechanism 5 for driving the barrel T to rotate. The support frame 10 is a mechanically welded frame, equipped with a brake wheel 11, including longitudinal members connected by cross beams. As Figure 2 Shown, brackets 12 can be provided at the longitudinal ends of the support frame 10 for hanging and connecting the cable 9 and the liquid pipeline 17 of the device D. Similarly, a pair of stabilizing blocks 13 can be installed on the upper longitudinal member of the support frame 10. The pair of stabilizing blocks form a frame arranged in a vertical plane, and this frame is suitable for the barrel T to pass through. The upper longitudinal member and the stabilizing blocks 13 are configured such that the longitudinal position of the stabilizing blocks 13 on the support frame 10 is adjustable, so as to adapt to the length of the component to be processed.

[0060] Alternatively, the frame assembly 1 may also include a movable frame (not shown) mounted on the support frame 10, which carries the mechanism 5 for driving the rotation of the barrel T. For example, the movable frame is mounted to pivot relative to the support frame 10 about a horizontal pivot axis perpendicular to the longitudinal axis of the support frame 10. The pivoting movement of the movable frame about the pivot axis is controlled by an oil cylinder connected to the support frame 10, and the oil cylinder is hinged to the movable frame about a rotation axis parallel to the pivot axis. Thus, in use, the extension of the actuator rod moves the movable frame and thus the barrel T supported thereby to a higher position, for example, a position where the longitudinal axis X0 of the barrel is horizontal. Conversely, the retraction of the actuator rod moves the movable frame and thus the barrel T to a lower position, where the longitudinal axis X0 of the barrel T forms an angle of 0-90 degrees with the horizontal plane. It should be noted that the actuator can be replaced by other suitable linear actuators. Therefore, such a frame assembly can adjust the barrel T to any desired inclination angle. To ensure the axial positioning of the barrel relative to the movable frame, especially in the case of a large inclination angle, an anti-slip ring can be installed on the outer circumference of the barrel, which abuts against the stop element of the movable frame.

[0061] Once the cathode 2 is connected to the negative pole (-) of the current source 8, this gives the barrel T the function of a cathode. As Figure 1 , 2 , 6 and 7 show, the cathode 2 includes metal guide rods 20 arranged along the outer wall of the barrel T, and is connected to the barrel T through a conductive connection flange 21 adapted to surround the barrel T. The guide rods 20 are connected to the current source 8 through a connection module 22. The module 22 is made of a conductive material and is adapted to surround the module 40A of the sealed interface mechanism 4A and the periphery of the guide rods 20, where the module 40A is made of an electrically insulating material. A conductive connection element 23 connected to the negative pole (-) of the current source 8 is accommodated in the connection module 22. Therefore, when the current source 8 is energized, the current flows along the electrical circuit CE through the connection element 23, and then successively through the connection module 22, the guide rods 20, the flange 21 and the wall of the barrel T.

[0062] The anode 3 is a longitudinal cylindrical component made of a conductive metal, especially copper and lead. As Figure 5 and 7 show, in the assembled state, the anode 3 is coaxially centered with the barrel T and protrudes outward from both ends E1, E2 of the barrel T. An annular channel is formed between the inner wall surface Pi of the anode 3 and the barrel T, and this channel defines a longitudinal passage 7 from one open end of the barrel T to the other end. Therefore, the diameter of the anode 3 is a function of the surface treatment to be implemented, for example, the thickness of the required metal deposition layer, and a function of the dimensional specifications of the barrel T.

[0063] As Figure 5As shown, the anode 3 is connected to the positive pole (+) of the current source 8 through the module 41B of the sealing interface mechanism 4B, where the module 41B is made of a conductive material. The module 41B houses a conductive connection element 30 connecting the current source 8 and cooperates with the end region of the anode 3. In particular, the end region of the anode 3 is provided with an external thread 31, which meshes with the threaded hole 413 of the module 41B. Therefore, when the current source 8 is energized, the current flows along the electrical circuit CE through the connection element 30 and then is conducted to the anode 3 through the conductive module 41B. As Figure 7 shown, the other end region of the anode 3 is provided with an axial threaded hole 32. A reinforcing rod 33 fixes the anode 3 to another conductive module 41A of the sealing interface mechanism 4A through its threaded end. The reinforcing rod 33 has a threaded longitudinal end region, and its external threads are respectively engaged with the threaded hole 413 of the conductive module 41A and the axial threaded hole 32 of the anode 3.

[0064] The sealing interface mechanisms 4A and 4B are used to seal the barrel T at the two open ends E1 and E2 of the barrel T to position the anode 3 inside the barrel T and to achieve the fluid communication between the processing liquid sources C1 to C n and the longitudinal passage 7 formed inside the barrel T. The sealing interface mechanisms 4A and 4B include a first interface assembly 4A and a second interface assembly 4B that respectively cooperate with the first end E1, the second end E2 of the barrel T and the anode 3.

[0065] As Figure 6 and 7 shown, the first interface assembly 4A includes a first module 40A made of an electrically insulating material, a first module 41A made of a conductive material, and a first tapered sealing connection module 42A.

[0066] The first module 40A made of an electrically insulating material is a tubular body, which is made of, for example, PVDF and has a hexagonal outer shape portion 401, a cylindrical portion 402, and an annular portion 403. The inner wall of the hexagonal outer shape portion 401 has an internal thread 404, which mates with the external thread T1 of the first end region E1 of the barrel T. Thus, the insulating module 40A is screwed and fixed to the first end E1 of the barrel T. The size of the cylindrical portion 402 is designed such that the connection module 22 can be adapted to its periphery. The through hole 405 of the insulating module 40A is coaxially arranged with the longitudinal axis X0 of the barrel T and the anode 3 so as to lead to the inside of the barrel T. The outer diameter of the annular portion 403 is larger than the outer diameter of the cylindrical portion 402, so that the module 40A can be assembled with the first conductive module 41A through detachable fasteners, especially bolts 43.

[0067] The first module 41A made of a conductive material is a tubular body, which is made of, for example, steel and has a cylindrical portion 410 inserted between two annular portions 411. The cylindrical portion 410 has a cylindrical hole 412 for positioning the first end region of the anode 3. The cylindrical hole 412 is coaxial with the longitudinal axis X0. The portion 410 can thus achieve the positioning of the anode 3 relative to the gun barrel T, in particular the centering. A threaded hole 413 engaged with the reinforcing rod 33 leads to the cylindrical hole 412. For this purpose, the anode 3 and its first end are fixed to the first conductive module 41A. One of the annular portions 411 is in contact with the annular portion 403 of the first insulating module 40A, and the two modules 40A and 41A are assembled in a sealed manner. The other annular portion 411 is in contact with the annular portion 420 of the first conical module 42A, and the two modules 41A and 42A are also hermetically connected by bolts 43, rings and seals. A plurality of cylindrical channels 414 are circumferentially arranged around the hole 412 coaxial with the gun barrel T. These channels 414 lead to the through hole 405 of the first insulating module 40A on the one hand and to the converging hole 423 of the first conical module 42A on the other hand.

[0068] The first conical module 42A is a tubular body made of an electrically insulating material, in particular plastic, and has an annular portion 420, a conical portion 421 and a cylindrical portion 422 for fixing the first conductive module 41A. The conical portion 421 is provided with a converging hole 423. The cylindrical portion 422 forms a cylindrical inlet / outlet end 424. The converging hole 423 communicates with the inlet / outlet end 424. For this purpose, the liquid from the treatment liquid sources C1 to C n can flow through the inlet / outlet end 424, the converging hole 423, the plurality of channels 414, the through hole 405 and the longitudinal passage 7 between the anode 3 and the gun barrel T in sequence.

[0069] As Figure 4 and 5 shown, the second interface assembly 4B includes a second module 40B made of an electrically insulating material, a second module 41B made of a conductive material, and a second conical sealing connection module 42B.

[0070] The second insulating module 40B is similar in structure to the first insulating module 40A and is threadedly fastened to the second end E2 of the gun barrel T. In particular, the internal thread 404 provided in the hexagonal outer shape portion 401, which is called the first threaded hole, cooperates with the external thread T2 in the second end region E2 of the gun barrel T.

[0071] The second module 41B made of a conductive material is similar to the first conductive module 41A, except that a radial hole 415 is provided at an annular portion 411 thereof that contacts the annular portion 403. The hole 415 is for accommodating a connecting element 30 that electrically connects the anode 3 and the current source 8. The region of the second end of the anode 3 penetrates through the cylindrical hole 412 and the threaded hole 413, and the external thread 31 of the anode 3 engages with the thread of the threaded hole 413, which is referred to as the second threaded hole. The pitch of the second threaded hole 413 is opposite to the pitch of the first threaded hole 404. For this purpose, when the anode 3 is positioned relative to the barrel T, the first end of the anode 3 is rotatably fixed by the rotation lock of the hexagonal outer portion 401. At this time, the second insulating module 40B on the second end E2 of the barrel T is tightened, so that the second end of the anode 3 is screwed into the second conductive module 41B, that is, away from the first end of the anode 3. The threaded holes 404 and 413 of the sealing interface mechanisms 4A and 4B thus constitute a mechanism that keeps the anode 3 under traction.

[0072] The second conical module 42B is similar to the first conical module 42A.

[0073] The mechanism 5 for driving the rotation of the barrel T is used to achieve the axial rotation of the barrel T. In other words, the barrel T is rotated about its longitudinal axis X0. In a preferred embodiment of the present invention, these mechanisms 5 can cause the barrel T to alternately perform a 360-degree axial rotation in a first rotation direction and a subsequent 360-degree axial rotation in a second opposite rotation direction.

[0074] As Figure 3As shown, these driving mechanisms 5 may include control devices, in particular a motor 50 carried by the upper longitudinal member of the frame assembly 1, and a transmission. The transmission includes a connecting rod 51 that is coupled to the output shaft of the motor 50 and is connected to a rack 52 of a rack and pinion system. Thus, the rotation of the motor 50 causes the rack 52 to translate alternately in a first direction and a second direction. The translational movement of the rack 52 in turn causes an associated gear 53 to rotate in one direction or the other. The gear 53 is coupled to a pulley belt assembly, with one pulley 54 mounted on a shaft coupled to the gear 53 and another pulley 55 mounted on a first rotating shaft of the roller assembly 57. Thus, the rotation of the gear 53 drives the rotation of the pulleys 54, 55 through a belt 56, thereby driving the rotation of the first rotating shaft carrying the roller assembly 57. The roller assembly 57 includes a first pair of rollers mounted on the first rotating shaft and a second pair of rollers mounted on a second rotating shaft, and the second rotating shaft is coupled to the first rotating shaft through another pulley belt assembly 58. The first and second rotating shafts are parallel to each other and parallel to the longitudinal axis X0. The two pairs of rollers 57 are disposed on both sides of the longitudinal axis X0 and below the barrel T so as to support the barrel T from below and transfer the rotational movement of the rollers 57 to the barrel T. The roller assembly 57 is supported by the upper longitudinal member of the frame assembly 1 in one of the longitudinal end regions of the frame assembly 1. In the other longitudinal end region of the frame assembly 1, a pair of rollers 59 are provided so as to be rotatable freely about rotation axes parallel to each other and freely about the longitudinal axis X0. These rollers 59 support the barrel T through a rolling ring assembly 60, which can be used to compensate for the taper of the barrel T. The rolling ring assembly 60 is mounted around the barrel T and is penetrated by the guide rod 20 of the cathode 2. Thus, the assembly including the barrel T, the cathode 2, the anode 3, and the seal interface mechanisms 4A, 4B can rotate when the barrel T rotates about its longitudinal axis X0.

[0075] As Figure 8 shown, for implementing surface treatment, the device D of the present invention is integrated into a surface treatment system S, particularly a closed-loop circulation operation system. The system S of the present invention includes an electrical circuit CE and a hydraulic circuit CH, both of which are connected to the aforementioned device D.

[0076] The electrical circuit CE includes a current source 8 and a cable 9. The cable conducts the positive electrode (+) of the current source 8 to the anode 3 by passing current through a connecting element 30 accommodated in the second conductive module 41B on the one hand, and conducts the negative electrode (-) of the current source 8 to the cathode 2 by passing current through a connecting element 23 accommodated in the connecting module 22 on the other hand.

[0077] The hydraulic circuit CH includes a plurality of treatment liquid storage tanks C1 to C that constitute at least one treatment liquid source n . Each storage tank C1 to C nConnect at least one upstream pipe 14 adapted to the solenoid valve 15, which is connected to a control device 16. The control device particularly includes a human-machine interface, an automatic control system with a probe, and sensors. A processing liquid circulation device, such as a pump, circulates the liquid through the upstream pipe 14. The downstream pipe 17 communicating with the upstream pipe 14 is fluidly connected to the inlet / outlet ends 424 of the first conical module 42A and the second conical module 42B, so that the processing liquid can circulate between one of the storage tanks C1 to C n and a longitudinal passage 7. The liquid circulation in the downstream pipe 17 is controlled by an alternating circulation mechanism 18, which alternates the circulation of one of the processing liquids in the longitudinal passage 7 in a first circulation direction and a second circulation direction ( Figure 8 as indicated by the double-headed arrow in). Thus, the processing liquid first enters the passage 7 through the first end E1 of the barrel T and is discharged from the second end E2 of the barrel T. Then, after a predetermined time, the processing liquid enters the passage 7 through the second end E2 of the barrel T and is discharged from the first end E1 of the barrel T. Figure 8 In, the indicated alternating circulation mechanism 18 is a reversible circulation pump driven by a drive motor, where the drive motor can rotate bidirectionally.

[0078] In operation, the operating method of the system S of the present invention includes the following preparatory steps:

[0079] - Mount the cathode 2 on the barrel T through two connecting flanges 21;

[0080] - Mount the rolling ring assembly 60 around the barrel T and the cathode 2;

[0081] - Mount the connecting module 22 around the first insulating module 40A;

[0082] - Fix the first insulating module 40A to the first end E1 of the barrel T, and the second insulating module 40B to the second end E2 of the barrel T. For this purpose, for each insulating module 40A, 40B, use a wrench matching the hexagonal profile 401 to screw the modules 40A, 40B onto the threads T1, T2;

[0083] - Fix the second conductive module 41B to the second insulating module 40B;

[0084] - Insert the anode 3 into the barrel T by inserting it from the first insulating module 40A until the second end thread 31 of the anode 3 engages with the threaded hole 413 of the second conductive module 41B;

[0085] - Fix the first conductive module 41A to the first end of the anode 3 by screwing the reinforcing rod 33 into the threaded hole 413, and then fix the first conductive module 41A to the first insulating module 40A;

[0086] - Keep the anode 3 under traction. To this end, the first operator uses a hexagonal wrench matching the hexagonal profile 401 to hold the first insulating module 40A in position relative to the barrel T, so that the first insulating module 40A and thus the first conductive module 41A and the anode 3 are rotationally locked. The second operator uses a corresponding wrench to tighten the second insulating module 40B onto the barrel T and applies a tightening torque of specifically 130 decinewton meters. Due to the reverse pitch of the threaded holes 404, 413, this tightening puts the anode 3 under traction between the two conductive modules 41A, 41B;

[0087] - Place the barrel T on the mechanism 5 for driving rotation carried by the frame assembly 1. To this end, the rolling ring assembly 60 is placed on the pair of freely rotating rollers 59, and the area of the barrel T located between the cathode 2 and the second interface assembly 4B is placed on the pair of rollers 57 driven by the motor 50 for rotation;

[0088] - Fix the first and second conical modules 42A, 42B to the first and second conductive modules 41A, 41B respectively;

[0089] - When necessary, especially in the case of a long barrel T, install brackets 12 on the support frame 10 and suspend the cable 9 and the hydraulic pipeline 17 from these brackets 12.

[0090] Once the above preparatory steps are completed, the barrel T to be processed can be used as the cathode, positioned in the required non-vertical orientation, especially the horizontal orientation, and the anode 3 is kept strictly coaxial with the longitudinal axis X0 of the barrel T.

[0091] The electrochemical treatment method may then include the following treatment steps:

[0092] - Connect the conical modules 42A, 42B to the hydraulic circuit CH;

[0093] - Connect the current source 8 to the cathode 2 by installing the connection module 22 around the first insulating module 40A and the guide rod 20, and connect the connection element 23 to the negative pole (-), and connect the current source 8 to the anode 3 by connecting the connection element 30 of the second conductive module 41B to the positive pole (+);

[0094] - Inject the electrolyte into the longitudinal passage 7 by starting the circulation mechanism and operating the control device 16;

[0095] - After the surface temperature of the barrel T is uniform, turn on the current source 8. The current passing through the treatment liquid flowing through the longitudinal passage 7 realizes the surface treatment of the inner wall Pi of the barrel T;

[0096] - During the surface treatment process, start the alternating circulation mechanism 18 of the treatment liquid and the mechanism 5 that drives the barrel T to rotate. In this way, the barrel T rotates in alternating directions around its longitudinal axis X0, and the treatment liquid flows longitudinally through the barrel T in one direction and then in the other longitudinal direction through the barrel T.

[0097] Once the surface treatment is completed, stop the circulation of the treatment liquid, empty the barrel T, disassemble the interface components 4A, 4B, and disconnect the device D from the electrical circuit CE and the hydraulic circuit CH.

[0098] Thus, it can be seen that the system S of the present invention can achieve continuous surface treatment processes. For example, according to the treatment requirements, the system S can perform the cleaning of the inner surface of the barrel B to prepare for subsequent processes such as coating attachment, electrolytic chrome plating to deposit a chromium layer, one or more rinses, electrolytic polishing, etc. The control device 16 of the hydraulic circuit CH realizes the above processes by controlling the fluid connection between the storage tanks C1 to C n and the device D. For example, during the cleaning process, the device D of the present invention passes through an etching solution (acidic, alkaline, etc.), and during the chrome plating process, the device D passes through a chromium-based solution. Therefore, the number of the storage tanks C1 to C n and the treatment liquid contained in these storage tanks are adapted to the required surface treatment. In addition, current is only passed through the electrical circuit CE when electrochemical treatment is carried out.

[0099] It should be understood that the above specific embodiments are only illustrative descriptions rather than restrictive descriptions, and various modifications can be made without departing from the protection scope of the present invention.

Claims

1. An apparatus (D) for electrochemically surface-treating the inner surface of a longitudinally tubular member (T) made of a conductive material, particularly for electrolytic metal plating of the inner wall (Pi) of a gun barrel (T), said tubular member (T) having a longitudinal axis (X0) and being open at a first end and a second end (E1, E2), the apparatus (D) comprising: - a frame assembly (1) configured to support said tubular member (T) so as to allow the tubular member (T) to rotate about its longitudinal axis (X0); - at least one cathode (2) for connecting to the negative pole of a current source (8) and configured to be electrically connected to the tubular member (T); - a longitudinal anode (3) for connecting to the positive pole of the current source (8), configured to be located inside the tubular member (T), coaxial with the longitudinal axis (X0) and extending along at least the entire length of the tubular member (T); - A sealing interface mechanism (4A, 4B), configured to removably mate with a tubular member (T) at a first end (E1) and a second end (E2) of the tubular member (T) and cooperate with the anode (3) to ensure its centered positioning relative to the tubular member (T), the sealing interface mechanism (4A, 4B) including at least one first inlet and outlet (424) adapted to communicate with a first open end (E1) of the tubular member (T), and at least one second inlet and outlet (424) adapted to communicate with a second open end (E2) of the tubular member (T), thereby forming, in use, a sealed longitudinal passage (7) from the first end (E1) to the second end (E2) of the tubular member (T), between the anode (3) and the inner surface of the tubular member (T), the inlet and outlet ends (424) being for connecting a source of treatment fluid (C1 - C n ) ; and - a mechanism (5) for driving the tubular member (T) to rotate about its longitudinal axis (X0), characterized in that said frame assembly (1) is adapted to support the tubular member (T) in a non-vertical direction, and the apparatus (D) further comprises a mechanism (6) for subjecting the anode (3) to traction, which is configured to act on at least one of the two ends of the anode (3) to prevent the anode (3) from flexing when the anode (3) is installed inside the tubular member (T).

2. The device (D) according to claim 1, characterized in that, The mechanism (6) for subjecting the anode (3) to traction is configured to adjust the traction force by screwing the anode (3) onto one of the sealing interface assemblies (4A, 4B).

3. The device (D) according to claim 1 or 2, characterized in that, The anode (3) traction mechanism (6) includes at least one first threaded hole (404) and at least one second threaded hole (413) provided in the sealing interface mechanism (4A, 4B), said one or one of the first threaded holes (404) being configured to cooperate with one of the ends (E1, E2) of the tubular member (T), particularly the second end (E2), said one or one of the second threaded holes (413) being configured to cooperate with the external thread (31) of the corresponding end region of the anode (3), and the pitch of the first threaded hole (404) being opposite to the pitch of the second threaded hole (413), such that in use, when the first threaded hole (404) is screwed onto the end of the tubular member (T) and the other end of the anode (3) remains fixed, the end region of the anode (3) having the external thread (31) is caused to screw into the second threaded hole (413).

4. The device (D) according to any one of claims 1 to 3, characterized in that, The sealing interface mechanism (4A, 4B) includes a first interface component (4A) and a second interface component (4B). The first interface component (4A) includes a first module (40A) made of an electrically insulating material, which is configured to cooperate with the first end (E1) of the tubular member (T) and is penetrated by the anode (3), and a first module (41A) made of a conductive material, which is fixed to the first module (40A) made of an electrically insulating material and is configured to cooperate with the first end of the anode (3). The second interface component (4B) includes a second module (40B) made of an electrically insulating material, which is configured to cooperate with the second end (E2) of the tubular member (T) and is penetrated by the anode (3), and a second module (41B) made of a conductive material, which is fixed to the second module (40B) made of an electrically insulating material and is connected to the second end of the anode (3) by a mechanism (6) that subjects the anode to traction.

5. The device (D) according to any one of claims 1 to 4, characterized in that, The at least one cathode (2) is an outer peripheral cathode and includes a metal guide rod (20), which is used to be located outside the tubular member (T) and arranged along its generatrix. The guide rod (20) is provided with at least one flange (21) for connecting the tubular member (T), and a connection module (22) for connecting the guide rod (20) to the current source (8). The connection module (22) is fixed to the sealing interface mechanism (4A, 4B) and is electrically isolated from the anode (3), so that the tubular member (T) functions as a cathode during use.

6. The device (D) according to any one of claims 1 to 5, characterized in that, The frame assembly (1) includes a support frame (10) and a movable frame, which is mounted on the support frame (10) and can move relative to the support frame (10), and can at least pivot about a pivot axis. The mechanism (5) for driving the tubular member (T) to rotate is fixed to the movable frame, and the amplitude of the pivoting of the movable frame about the pivot axis is such that during use, the inclination angle of the tubular member (T) relative to the horizontal plane is within a range including 0 to 90 degrees.

7. The device (D) according to any one of claims 1 to 6, characterized in that, The mechanism (5) for driving the tubular member (T) to rotate is configured to generate an alternating rotational movement of the tubular member (T), so that during use, the tubular member (T) can rotate alternately in a given rotational direction and then in the opposite rotational direction within a given angular range.

8. A system (S) for electrochemically surface treating the inner surface of a tubular member (T) made of a conductive material, characterized in that, Comprising the device (D) according to any one of claims 1 to 7, and the system (S) further includes: - An electrical circuit (CE), which includes a current source (8), whose positive pole is connected to the anode (3) and whose negative pole is connected to the at least one cathode (2); - Hydraulic circuit (CH), connected to the first inlet and outlet ends and the second inlet and outlet ends (424) of the device (D), and comprising at least one source of treatment fluid (C1 - C n ), and a circulation device; the hydraulic circuit (CH) further includes an alternating circulation mechanism (18) capable of causing the treatment fluid to circulate in the longitudinal passage (7) from the first end (E1) to the second end (E2) in a first step and then in a reverse direction from the second end (E2) to the first end (E1) in a second step.

9. The system (S) according to claim 8, characterized in that, The anode (3) is connected to the current source (8) through a first conductive connection element (30), which is connected to the positive pole of the current source (8) on the one hand and to the second module (41A; 41B) made of a conductive material on the other hand, and the cathode (2) is connected to the current source (8) through a second conductive connection element (23), where the second conductive connection element is connected to the negative pole of the current source (8) on the one hand and to the connection module (22) on the other hand.

10. The system (S) according to claim 8 or 9, characterized in that: The hydraulic circuit (CH) includes a plurality of processing liquid storage tanks (C1-C n ), each tank (C1-C n ) being in communication with at least one pipe (14), wherein at least one pipe is used to convey the liquid it contains, the pipe (14) is provided with a solenoid valve (15), and a control device (16) is provided, the control device being used to control the solenoid valve (15) so that one of the storage tanks (C1-C n ) is in fluid communication with the device (D).

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