CN113020765A

CN113020765A - Electrode wheel with detachable ring

Info

Publication number: CN113020765A
Application number: CN202011446167.2A
Authority: CN
Inventors: N.劳雷恩; M.比登巴赫
Original assignee: Gaztransport et Technigaz SA
Current assignee: Gaztransport et Technigaz SA
Priority date: 2019-12-09
Filing date: 2020-12-09
Publication date: 2021-06-25
Also published as: KR20210072728A; FR3104044A1; SG10202012144YA; FR3104044B1

Abstract

The invention relates to an electrode wheel (1) for welding metal sheets (50, 52), the wheel (1) comprising at least a disc (2) made of a first material and a ring (4) made of a second material different from the first material, assembly means allowing the ring (4) to be assembled on the disc (2).

Description

Electrode wheel with detachable ring

Technical Field

The field of the invention is electrode wheels, more particularly for continuously welding metal sheets that constitute the walls of tanks for storing and transporting liquefied natural gas.

Background

A storage tank for storing and transporting Liquefied Natural Gas (LNG) consists of a tank wall, which comprises inter alia insulation sections and metal plates ensuring a tight sealing of the tank wall. In order to sealingly attach the metal plates together, it is known to weld them to each other. In fact, welding the metal plates ensures an optimal sealing of the tank and an effective attachment of the metal plates to each other. To this end, it is known to use a welding machine comprising at least one electrode wheel adapted to weld metal sheets under the action of an electric current flowing through the electrode wheel. Such electrode wheels are made of alloys of different metals, having conductive properties compatible with the voltages and currents in question. However, certain metals, such as beryllium, that make up the alloy have a high cost.

To reduce the time required to manufacture the above-mentioned tanks, the speed of movement of the wheel-carrying welder is increased, resulting in an increase in the frequency of the current flowing through the wheel and in the intensity of the current passing through it. However, these increases have the disadvantage that the probability of overheating in the latter increases considerably. In fact, the applicant has noticed that the current structure of the wheel is not optimal in terms of such an increase in the frequency and intensity of the withstand current, and this has the consequence of shortening its service life, in particular due to wear of the wheel.

As the service life of the wheel is shortened, it is necessary to replace the wheel more frequently than before increasing the frequency and intensity of the current, thereby increasing the main cost of the operator over time.

The object of the present invention is therefore to overcome the above mentioned drawbacks by devising a two-part electrode wheel, one part of which, comprising a higher concentration of noble metal, can be separated from the other part and replaced independently of the latter, so that it can be reused to carry a new part dedicated to welding.

Disclosure of Invention

The invention therefore relates to an electrode wheel for welding metal sheets, comprising at least a disk made of a first material and a ring made of a second material different from the first material, the ring circumferentially surrounding the disk, characterized in that it comprises at least one assembly device allowing the ring to be detached from the disk.

According to the invention, the assembly means can be an assembly by force fit or by screwing the ring onto the disk. In other words, the assembly means may be a forced mounting of the ring to the disc, or a screwing of the ring to the disc.

The invention thus allows to increase the rotation speed of the wheel without requiring an increase in the wheel size, while keeping in particular the operating costs of the welder equipped with such a wheel at an amount compatible with the limits of the factory.

Electrode wheels are used, for example, for welding metal plates constituting the walls of storage tanks for storing and/or transporting Liquefied Natural Gas (LNG). Such tank walls are composed, inter alia, of insulating sections, which are necessary for the cryogenic transport of LNG,and also comprising a plurality of metal sheets, e.g. made of

Or indeed from high alloys or from stainless steels. The function of the metal plate is to ensure a tight sealing of the tank. According to one embodiment of the tank wall, the metal plate may have a raised edge at the periphery. The electrode wheel is then used to weld the raised edges of adjacent metal sheets. Welding the raised edges in this manner ensures optimal sealing of the tank for storing and/or transporting LNG.

The disk of the wheel corresponds to the central part of the wheel intended to be attached to the welder. According to the invention, the disc of the wheel comprises two distinct portions which are brazed together to form the disc. More precisely, the disc comprises a first portion and a second portion, each comprising at least one part of a hole for attaching the disc to a welder, the assembly of the first portion and the second portion of the disc forming the hole by brazing. The advantage of this configuration of the disc is that it requires fewer parts to form the disc and that the disc is thinner than the discs of the known solutions.

The ring assembled around the disc of the wheel corresponds to the portion of the wheel intended to come into contact with the metal sheets to be welded. For this purpose, the ring forms an electrode which is activated under the effect of the current flowing in the wheel, and the activation of this electrode causes a significant increase in the temperature of the wheel.

Significant increases in temperature can lead to overheating, which can reduce the useful life of the wheel over time. It will therefore be appreciated that the advantage of a ring which can be separated from the disc by the assembly means is that it allows worn rings to be replaced without the need to replace the entire wheel. This reduces the cost to the welder operator.

According to the invention, the first material and the second material are different and both have conductive properties compatible with the welding operation, i.e. suitable for the current to flow through the ring of the wheel.

According to one feature of the invention, the ring defines an inner space housing the disc. In other words, the ring circumferentially surrounds the disk, which in turn carries the ring.

According to one feature of the invention, the ring comprises an inner face facing the inner space and an outer face opposite the inner face, the outer face of the ring forming the contact surface of the wheel. The contact surface of the wheel constitutes the part of the wheel intended to be in contact with the metal sheets to be welded. In other words, the contact surface of the wheel forms the welding surface.

According to one feature of the invention, the ring is annular and the contact surface is therefore circular.

Thus, it should be understood that the ring is circular and its inner face defines an inner space, which may be any shape that matches the outer shape of the disc. The contact surface is understood to mean the fact that the external face corresponds to the face of the ring intended to be in contact with the metal sheet to be welded. Thus, it should be understood that the plurality of electrodes of the wheel are located in the contact surface. Thus, the circular contact surface allows for continuous welding in a continuous motion along the metal sheet.

According to one feature of the invention, the assembly means comprise an inner face of the ring facing the inner space and an outer face formed at the periphery of the disc.

It will be appreciated that when the disc is inserted into the inner space of the ring, the inner face of the ring forms, together with the outer surface of the disc, the assembly means of the wheel. In other words, the inner face of the ring and the outer face of the disc can cooperate in a manner that secures the disc to the ring. This fit may be achieved by press fitting the disc into the ring.

According to one feature of the invention, the outer surface of the disc includes a radially extending shoulder, and the ring includes a bearing surface disposed against the shoulder. The bearing surface contacts the shoulder and limits axial movement of the ring relative to the disk.

According to one example of the invention, the shoulder comprises at least one receiving edge extending in a perpendicular direction from the outer surface of the disc. Thus, the bearing surface of the ring is arranged to abut against the receiving edge of the shoulder. The shoulder has in particular the function of increasing the retention of the ring around the disc by forming an abutment zone where the ring abuts against the disc. Also, when the wheel is mounted on a welding machine and rotated during welding, the shoulder helps to retain the ring on the disk to prevent the two from separating from each other.

According to one feature of the invention, the wheel extends mainly in a main plane, the shoulder has a first width measured along a line parallel to the main plane of the wheel between the outer surface of the disc and the peripheral free edge of the shoulder, and the ring has a radial dimension measured along the bearing surface along a line parallel to the main plane of the wheel, said radial dimension being strictly greater than the first width.

The advantage of this function is that it allows to place the outer face of the ring in the position furthest from the centre of the wheel. In other words, the ring protrudes from the outer surface of the disc. Thus, when the wheel is used for welding metal sheets, only the contact surface formed by the outer faces of the rings is in contact with the metal sheets. This ensures the accuracy of the welding operation and reduces wear on other parts of the wheel.

According to one feature of the invention, the disc comprises a first face and a second face opposite to each other in a vertical direction of the wheel, the first face extending in a first main plane of the first face parallel to the main plane of the wheel and the second face extending in a second main plane of the second face parallel to the main plane of the wheel, the ring being contained within a space axially delimited by the first main plane of the first face and the second main plane of the second face.

Advantageously, the ring extends for an axial distance that is less than the axial distance over which the space formed by the first and second main planes extends. This feature has the advantage that it reduces the vertical dimension of the ring, thereby reducing the cost of the operator to replace the ring.

According to an alternative of the invention, the inner face of the ring comprises a radially extending shoulder, which is in contact with the disc.

When the ring is mounted on the disc, the shoulder of the inner face of the ring may extend, for example, along the first or second face of the disc. This increases the mechanical attachment of the ring to the disc after assembly.

According to one feature of the invention, the outer surface of the disc is in contact with the inner face of the ring.

According to one example of the invention, the contact between the outer surface of the disc and the inner face of the ring forms the assembly means of the wheel. Thus, assembling the device may include, for example, press fitting or screwing the ring onto the disc.

According to one feature of the invention, the wheel comprises a cooling system comprising at least a first cooling circuit and a second cooling circuit separate from the first circuit.

The function of the cooling system is to cool the wheel during use. In particular, the cooling system with the double cooling circuit contributes to increasing the cooling of the wheel and allows increasing the frequency and intensity of the current passing through the wheel.

More precisely, the cooling system is made inside the disc. It will therefore be appreciated that each of the first portion of the disc and the second portion of the disc comprises a part of the cooling system, such that brazing of the two portions of the disc forms the cooling system.

According to a feature of the invention, said first material is an alloy comprising at least copper and said second material is an alloy in which at least one metal is chosen from beryllium, chromium, cobalt, zirconium, cadmium, tin and/or tungsten.

One advantage of the second material comprising a metal selected from the above list is that the second material has superior electrical conductivity and heat resistance compared to the first material. Similarly, the second material has better wear resistance than the first material and increases the wear resistance of the ring, thus allowing the use of expensive metals for manufacturing the ring.

The invention also relates to a method of assembling an electrode wheel according to any of the preceding features, comprising at least a ring and a disk, in which method the ring is force-fitted onto the disk during at least one step.

The press-fit operation involves inserting the disc into the interior space of the ring and then contacting the outer surface of the disc with the interior face of the ring. Thus, the circumference of the inner space of the ring is smaller than the diameter of the disc defined by the outer surface of the disc. The press fit in this way ensures the possibility of removing the ring from the disk, the electrical conductivity of the disk with the ring and the thermal conductivity from ring to disk.

According to an alternative of the invention, at least one step of the method consists in screwing the ring onto the disk. The assembly means of the wheel may thus consist of a thread connecting the ring to the disc. More specifically, the disc includes a first thread on its outer surface and the ring includes a second thread on its inner face. According to one embodiment, the direction of screwing the assembly device by means of screws is opposite to the direction of rotation of the electrode wheel when used to implement the welding method or welding machine.

The invention also relates to a welding machine for connecting a first metal plate and a second metal plate of a tank for storing and/or transporting liquefied natural gas, comprising at least one wheel according to any one of the preceding features.

According to an example of the invention, a welding machine comprises a first electrode wheel and a second electrode wheel according to the invention. The first and second wheels are then arranged on both sides of the raised edge of the metal sheet of the tank to be welded. The first electrode wheel is brought to a first potential and the second electrode wheel is brought to a second potential opposite to the first potential. The welding wheel is therefore an electrode which reaches the above-mentioned potential in a discontinuous manner, at a given frequency and intensity higher than those normally used.

According to one feature of the welder, it is configured to perform continuous welding at a speed greater than or equal to two meters half/minute. The continuous welding is advantageously carried out at a speed of 4 m/min.

Drawings

Further characteristics, details and advantages of the invention will become clearer from reading the following description on the one hand and from providing several embodiments on the other hand as a non-limiting example with reference to the attached schematic drawings, in which:

FIG. 1 is a general perspective view of a first face of a wheel according to the present invention, including a disk and a ring;

FIG. 2 is a general perspective view of a second face of the wheel of FIG. 1;

FIG. 3 is an axial cross-sectional view of the wheel of FIG. 1, showing a disk including a cooling system and a shoulder;

FIG. 4 is a general perspective view of the ring of the wheel;

FIG. 5 is an axial cross-sectional view of the wheel of FIG. 1, showing the arrangement of rings on the disk;

FIG. 6 is a close-up view of the ring in contact with the disk and secured together by screws;

fig. 7 is a schematic view of a welding machine according to the invention, which is connected to a first electrode wheel and a second electrode wheel according to the invention.

Detailed Description

The features, variations and different embodiments of the present invention can be associated with each other in various combinations, as long as they are incompatible or mutually exclusive with each other. In particular, variants of the invention may be envisaged which merely involve a selection of the features described below in isolation from other described features, if the selection of the features is sufficient to enable the invention to have technical advantages over or to be distinguished from the prior art.

Fig. 1 shows an electrode wheel 1 according to the invention. The electrode wheel 1 can be used for welding metal plates together by continuous welding and spot welding. To this end, the electrode wheel 1 is attached to a welding machine (shown in fig. 7) that continuously moves at a speed greater than or equal to two meters half per minute along the metal sheet. The movement of the welding machine thus ensures the movement of the wheel 1 and the circulation of the current inside the wheel, allowing the wheel 1 to perform its welding function.

Such a wheel 1 may be used, for example, when manufacturing storage tanks for transporting and storing Liquefied Natural Gas (LNG). Such a tank consists for example of at least one insulating barrier for insulating the tank, in particular its cargo, and a plurality of metal plates for sealing it and comprising for example one or more raised edges. The wheel 1 is then required to attach the raised edges of the adjacent metal sheets. Welding the raised edges of the metal plates by means of the electrode wheels 1 ensures in particular an optimal and durable sealing of the tank for transporting and storing LNG.

The electrode wheel 1 shown in fig. 1 and 2 is circular and extends in the main plane M of the wheel 1. Thus, the electrode wheel 1 has a central axis of rotation X passing through the centre D of the wheel 1. According to the invention, the wheel 1 comprises a disc 2 and a ring 4, which are removable from each other. Detachable is understood to mean the fact that in the initial state the ring 4 and the disc 2 are separated from each other and that in the final state they are assembled by the assembly device during the assembly method. The assembly device and the assembly method will be set forth in more detail later in the detailed description.

The disc 2 of the wheel 1 shown in figures 1, 2 and 3 is circular and comprises a peripheral outer surface 6 defining a first diameter D1 of the disc 2. The disc 2 also comprises a first face 8, in particular shown in fig. 1, and a second face 10, in particular shown in fig. 2, the second face 10 being opposite the first face 8, perpendicular to its main plane M, in the vertical direction V of the wheel 1.

On the first face 8 of the disc 2 there is provided a circular central cavity 12, this circular central cavity 12 being shown in particular in fig. 3, fig. 3 showing an axial section of the wheel 1 according to a first plane a-a. The central lumen 12 is surrounded by a circular lumen rim 14, and a second diameter D2 is defined as the diameter corresponding to the circumference of the central lumen 12. The second diameter D2 is strictly smaller than the first diameter D1 of the disc 2.

The central cavity 12 should be understood to refer to the fact that material has been removed from the first side 8 of the disc 2, thereby forming a recess in the disc 2. The function of the central cavity 12 is to form a fool-proof means for centering the electrode wheel 1 for its assembly on the hub of the welding machine. The central cavity 12 helps to centre the wheel 1 on the hub. Thus, it will be understood that the first side 8 of the disc 2 is the side facing the welding machine.

Once the electrode wheel 1 is positioned on the welding machine, at least one through hole 16 provided in the disk 2 helps to fix the electrode wheel 1 to the welding machine. The through hole 16 is understood to mean the fact that the through hole 16 passes completely through the wheel 1, i.e. the hole 16 appears on the first face 8 and on the second face 10 of the disc 2, as shown in figure 3. Thus, the holes 16 can cooperate with fastening means, such as screws, in order to fix the wheel 1 with the welding machine. According to one example of the invention, shown in particular in fig. 3, the hole 16 has a counterbore with a diameter greater on the second face 10 of the disc 2 than on the first face 8. This feature makes it possible in particular to accommodate the screw head in a plane coinciding with the second main plane P2 of the second face 10.

According to the embodiment shown, the wheel 1 comprises four through holes 16 provided on the disc 2. Four holes 16 are advantageously distributed around the periphery in the central chamber 12 in order to better retain the wheel 1 on the welding machine.

As shown, in particular, in fig. 3, in the initial condition, the disc 2 of the wheel 1 is not provided with a ring. The assembly means enable the assembly of the ring on the disc 2 during the assembly method; the assembly means may for example comprise press fitting or screwing the ring around the disc 2. The fact that the ring can be separated from the disc 2 is advantageous because it allows the ring of the wheel 1 to be replaced when worn, without the disc 2 having to be replaced.

The wheel comprises a cooling system 18 arranged in its disc 2. The cooling system 18 advantageously comprises a first cooling circuit 20 and a second cooling circuit 22, partially shown in fig. 3. The cooling system 18 comprises an inlet 24 and an outlet 26 for allowing coolant to enter the electrode wheel 1, and these are arranged in the central cavity 12 of the disk 2, as shown in fig. 1.

The function of the cooling system 18 is to cool the wheel 1 during use of the wheel 1, i.e. when current flows through the wheel. In particular, the cooling system 18 helps to limit the temperature of the wheel 1 and therefore reduces the occurrence of overheating which can cause damage to the wheel over time. One advantage of the cooling system 18 comprising a double cooling circuit is that it increases the cooling effect on the wheel 1 and contributes to increasing its service life.

According to a characteristic of the invention, the disc 2 of the wheel is made in two parts. More precisely and as shown in fig. 3 or 5, the disc 2 comprises a first portion 2a and a second portion 2 b. Each of the two

portions

2a, 2b of the disc 2 comprises a part of the aforementioned four holes 16 and a part of the inlet 24 and outlet 26 of the cooling system 18. It will therefore be appreciated that each sub-portion of the bore 16, of the inlet 24 and of the outlet 26 is made in each of the first and

second portions

2a, 2b, such that assembly of the two

portions

2a, 2b integrally forms the bore 16, the inlet 24 as a whole and the outlet 26 as a whole, as previously described.

The first portion 2a and the second portion 2b of the disc 2 are assembled together by brazing along an assembly line Y included in a radial plane of the disc 2. The advantage of this configuration of the disc 2 is that it requires only the first portion 2a and the second portion 2b to form said disc 2 of the wheel, without adding any other elements, and the brazed assembly allows to obtain the final disc 2. The shoulder 28 extends radially from the outer surface 6 of the disc 2. According to the example of the invention shown, the shoulder 28 extends substantially perpendicularly to the outer surface 6 and comprises a peripheral free edge 30, this peripheral free edge 30 being connected to the outer surface 6 of the disc 2 by a receiving edge 32 and an inclined edge 34. More specifically, the inclined edge 34 extends from the second face 10 of the disc 2 and extends towards the first face 8 of the disc 1 at an inclination angle of between 10 ° and 80 ° with respect to the main plane M of the wheel 1.

The receiving edge 32 extends in the vertical direction V of the wheel 1 in the vertical direction from the outer surface 6 opposite the inclined edge 34. Thus, peripheral free edge 30 extends between receiving edge 32 and inclined edge 34 perpendicularly to main plane M of wheel 1, and such that peripheral free edge 30 connects receiving edge 32 and inclined edge 34.

The shoulder 28 comprises a first width E1 measured along a line parallel to the main plane M of the wheel 1 between the outer surface 6 of the disc 1 and the peripheral free edge 30 of the shoulder 28.

The ring 4 will now be described separately with reference to fig. 4. The ring 4 is a circular ring and defines an inner space 36 in which the disc 2 of the wheel 1 can be accommodated. More specifically, ring 4 comprises, in a main plane M of wheel 1, an inner face 38 facing towards inner space 36 and an outer face 40 radially opposite inner face 38. Accordingly, the inner face 38 defines an interior space 36 having a circumference with a third diameter D3. According to one example of the invention, third diameter D3 may be substantially equal to or less than first diameter D1 of disk 2 of wheel 1, thereby ensuring that ring 4 is press-fit onto disk 2.

The outer face 40 of the ring 4 defines a contact surface 42 of the wheel 1, and it will therefore be appreciated that this contact surface 42 is circular. The contact surface 42 is understood to be the face 40 of the outer ring 4 corresponding to the face of the ring 4 in contact with the metal sheets to be welded. The contact surface 42 thus forms a welding surface of the wheel 1. To this end, the ring 4 forms an electrode which is activated by the current flowing in the wheel 1 to allow the welding of the metal sheets.

The ring 4 of the wheel 1 is axially delimited by a bearing surface 44 and a top face 46 shown in fig. 5. In other words, the top face 46 and the bearing surface 44 extend radially and parallel to the main plane M of the wheel 1, so that they are opposite each other in the vertical direction V of the wheel 1.

Inner face 38 of ring 4 extends in a vertical direction between top face 46 and support surface 44 of ring 4 such that inner face 38 of ring 4 connects top face 46 and support surface 44 of ring 4. Outer face 40 and inclined face 48 extend opposite inner face 38 in the radial direction of wheel 1, and so that they connect top face 46 and bearing surface 44. More specifically, outer face 40 extends in a vertical direction from support surface 44, and inclined face 48 extends from top face 46, and thus, it should be appreciated that inclined face 48 extends between outer face 40 and top face 46.

The radial dimension R1 is defined as the width of the ring 4 measured between the inner face 38 and the outer face 40 of the ring 4 along a line parallel to the radial direction of the wheel 1. According to a feature of the invention, the radial dimension R1 is strictly greater than the first width E1 of the shoulder 28. This feature allows the contact surface 42 of the wheel 1, defined by the outer face 40 of the ring 4, to protrude from the rest of the wheel 1, in order to perform the welding of the metal sheets.

As shown in fig. 5, which shows an axial section according to the first plane a-a shown in fig. 1, the bearing surface 44 of the ring 4 comes into contact against the receiving edge 32 of the shoulder 28 when the ring 4 is assembled with the disc 2. Similarly, the inner face 38 of the ring 4 is in contact with the outer surface 6 of the disc 2. It will be understood that the function of the shoulder 28 is to form an axial abutment area for the ring 4 when assembling the ring 4 on the disc 2.

According to one characteristic of the invention, a second thickness E2 of disc 2 is defined, measured along a line parallel to the axial direction of wheel 1, between first face 8 and second face 10. Furthermore, a third thickness E3 of ring 4 is defined between top face 46 and bearing face 44, measured along a line parallel to the vertical direction V of wheel 1. Therefore, the third thickness E3 of the ring 4 is strictly smaller than the second thickness E2.

Moreover, according to the invention, the third thickness E3 of the ring 4 lies within the space axially delimited by the first main plane P1 of the first face 8 of the disc 2 and by the second main plane P2 of the second face 10 of the disc 2. Advantageously, the third thickness E3 of the ring 4 is smaller than the axial distance extended by the space defined by the first main plane P1 and the second main plane P2. Such a feature helps to limit the axial dimension of the ring 4 and thus enhances its retention to the outer surface 6 of the ring 4. The amount of material comprising ring 4 may also be included.

According to a feature of the invention, the first material constituting the disc 2 is, for example, a material such as copper. Instead, the second material constituting the ring 4 may be an alloy made of a noble material such as beryllium, chromium, cobalt, zirconium, cadmium, tin and/or tungsten. Thus, it can be seen that the advantage of the wheel 1 comprising a ring 4 that can be separated from the disc 2 is that the disc 2 can be retained and reused as long as it is possible to replace only the ring 4 of the wheel when the ring 4 is worn. This helps to limit the replacement costs of the wheel 1 due to its particular composition, the wheel 1 possibly containing materials that are expensive for the welder operator.

According to a feature of the invention, the ring 4 can be force-fitted onto the disc 2. This force fit operation is possible because the first diameter D1 of the disc 2 is greater than the second diameter D2 of the interior space 36 defined by the interior face 38 of the ring 4.

According to a second embodiment of the assembly device shown in fig. 6, the ring 4 can be screwed onto the disc 2 by means of a thread 39. More specifically, a first thread 39a is provided on the outer surface 6 of the disc 2 and a second thread 39b is provided on the inner face 38 of the ring 4 opposite the first thread 39 a. It is to be noted that the direction of screwing the assembly device by screws is opposite to the direction of rotation of the electrode wheel 1 when the electrode wheel 1 is used by the welding method forming the subject of the invention, or when the wheel is mounted on a welding machine and the welding machine forms a weld bead. This ensures a fit between the ring 4 and the disc 2 and ensures that setting the wheel 1 to rotate during the welding process does not cause the ring 4 to disengage from the disc 2.

According to an alternative of the invention, not shown here, the shoulder may extend radially from the inner face of the ring, so that the shoulder is in contact with the first face or the second face of the disc of the wheel. Thus, it should be understood that in this embodiment, the outer face is flat.

The welding method will now be described with reference to fig. 7, which shows a first 50 and a second 52 metal plate having a first 54 and a second 56 raised edge, respectively. The first and second raised

edges

54 and 56 are arranged to face each other.

The welding machine 58 of fig. 7 is shown schematically, and it will be understood that its dimensions and arrangement relative to the welding wheel 1 are not shown to scale. Similarly, the electrical connection between the welder 58 and the welding wheel 1 is not shown, but it should be understood that the welder 58 allows for the supply of electrical current to the welding wheel 1 as already described above in the detailed description.

The first welding wheel 1a and the second welding wheel 1b are arranged on both sides of the raised

edges

54, 56 of the

metal sheets

50, 52. More specifically, the first welding wheel 1a faces the first raised edge 54 and the second welding wheel 1b faces the second raised edge 56. Thus, the first contact surface 42a of the first wheel 1a is in contact with the first raised edge 54 and the second contact surface 42b of the second wheel 1b is in contact with the second raised edge 56.

When implementing the method for welding the

metal sheets

50, 52, the welding machine 58 is moved forward using an external device (not shown here). As the welder 58 moves, it sends an electrical current to the welding wheels 1a, 1b, thereby creating a weld bead 62. Activation of the plurality of electrodes allows welding together the raised

edges

54, 56 of the

metal plates

50, 52, but also results in a significant increase in temperature at the contact surfaces 42a, 42b of the electrode wheels 1a, 1 b.

In order to prevent overheating due to high temperatures, the first wheel 1a and the second wheel 1b comprise a first cooling system and a second cooling system, respectively. Each of the first and second cooling systems includes the previously disclosed first and second cooling circuits.

A first rotary shaft 61a extends between the first welding wheel 1a and the welder 58 and a second rotary shaft 61b extends between the second welding wheel 1b and the welder 58. In order to irrigate the first and second cooling circuits of each wheel 1a, 1b with coolant, a plurality of pipes 60 connect the latter to the welder 58.

The plurality of pipes 60 extend into each of the first and

second rotation shafts

61a and 61 b. Specifically, a first pipe 60a connected to the first inlet, a second pipe 60b connected to the first outlet, a third pipe 60c connected to the second inlet, and a fourth pipe 60d connected to the second outlet extend into the first rotation shaft 61 a. The second cooling system of the second welding wheel 1b employs the same configuration between the duct 60 provided in the second rotation shaft 61b and the inlet and outlet.

Thus, the plurality of conduits 60 irrigate the cooling system of the wheels 1a, 1b with coolant to prevent overheating of the wheels 1a, 1b when high frequency and high intensity current flows through the welding surfaces 42a, 42b of the wheels 1a, 1 b.

The invention thus achieves the stated object by proposing an electrode wheel whose structure allows higher frequencies and higher intensities of current to flow into it, and whose replacement is optimized for reduced costs. This allows for faster welding of the raised edges of the metal plates, thereby reducing the time required to manufacture the tank wall for storing or transporting LNG.

The invention, however, is not limited to the devices and configurations specifically described and illustrated herein, and is also applicable to all equivalent devices or configurations, as well as any combination of such devices or configurations.

Claims

1. Electrode wheel (1) for welding metal sheets (50, 52), the wheel (1) comprising at least a disc (2) made of a first material and a ring (4) made of a second material different from the first material, the ring (4) peripherally surrounding the disc (2), the wheel (1) being characterized in that the wheel (1) comprises at least one assembly device allowing the ring (4) to be detached from the wheel (2), the assembly device being intended for force-fitting or screwing the ring (4) onto the disc (2).

2. Electrode wheel according to claim 1, wherein the ring (4) delimits an inner space (36) accommodating the disk (2).

3. Electrode wheel (1) according to claim 2, wherein the ring (4) comprises an inner face (38) facing the inner space (36) and an outer face (40) opposite the inner face (38), the outer face (40) of the ring (4) forming a contact surface (42) of the wheel (1).

4. Electrode wheel (1) according to claim 3, wherein the assembly means comprise an inner face (38) of the ring (4) facing the inner space (36) and an outer face (6) formed at the periphery of the disc (2).

5. The electrode wheel (1) according to claim 4, wherein the outer surface (6) of the disc (2) comprises a radially extending shoulder (28), the ring (4) comprising a bearing surface (44) arranged against the shoulder (28).

6. Electrode wheel (1) according to claim 5, wherein the wheel (1) extends mainly in a main plane (M), the shoulder (28) has a first width (E1) measured between the outer surface (6) of the disk (2) and the peripheral free edge (30) of the shoulder (28) and along a line parallel to the main plane (M) of the wheel (1), and the ring (4) has a radial dimension (R1) measured along the bearing surface (44) and along a line parallel to the main plane (M) of the wheel (1), the radial dimension (R1) being strictly greater than the first width (E1).

7. Electrode wheel (1) according to claim 6, wherein the disc (2) comprises a first face (8) and a second face (10) opposite each other in a vertical direction (V) of the wheel (1), the first face (8) extending in a first main plane (P1) of the first face (8) parallel to a main plane (M) of the wheel (1) and the second face (10) extending in a second main plane (P2) of the second face (10) parallel to the main plane (M) of the wheel (1), the ring (4) being contained within a space axially delimited by the first main plane (P1) of the first face (8) and by the second main plane (P2) of the second face (10).

8. The electrode wheel (1) according to any of the preceding claims, wherein the wheel (1) comprises a cooling system (18) comprising at least a first cooling circuit (20) and a second cooling circuit (22).

9. The electrode wheel (1) according to any of the preceding claims, wherein the first material is an alloy comprising at least copper and the second material is an alloy wherein at least one metal is selected from beryllium, chromium, cobalt, zirconium, cadmium, tin or tungsten.

10. Method of assembling an electrode wheel (1) according to any of the preceding claims, comprising at least a ring (4) and a disk (2), in which method the ring (4) is force-fitted onto the disk (2) during at least one step.

11. Method of assembling an electrode wheel (1) according to any one of claims 1 to 9, comprising at least a ring (4) and a disk (2), in which method the ring (4) is screwed onto the disk (2) during at least one step.

12. A welding machine (58) for connecting a first metal plate (50) and a second metal plate (52) of a tank for storing and/or transporting liquefied natural gas, comprising at least one electrode wheel (1) according to any one of claims 1-9.

13. The welder (58) of claim 12, configured to perform the continuous welding at a speed greater than or equal to two meters half per minute.