CN116967660A

CN116967660A - Welding machine

Info

Publication number: CN116967660A
Application number: CN202310475029.4A
Authority: CN
Inventors: M·比登巴赫; N·洛兰
Original assignee: Gaztransport et Technigaz SA
Current assignee: Gaztransport et Technigaz SA
Priority date: 2022-04-29
Filing date: 2023-04-27
Publication date: 2023-10-31
Also published as: KR20230153957A; FR3135004A1

Abstract

The invention relates to a welding machine (1) for at least two parts to be welded, the welding machine (1) comprising at least one moving assembly (10) comprising at least one pair of driving wheels for moving said moving assembly (10) relative to the parts to be welded; at least one welding head (14) comprising at least two welding wheels (16) capable of welding the parts to be welded; and at least one converter (18) for supplying welding current to the welding head (14), the welding machine (1) comprising a cooling device (24) of the moving assembly (10), the cooling device (24) comprising at least one cooling circuit (26) passing through the moving assembly (10).

Description

Welding machine

Technical Field

The invention relates to a welding device comprising an electrode in the form of a welding wheel for welding together parts to be welded.

Background

Current welders include a drive wheel and a welding wheel that can weld the parts to be welded, and a drive member that can at least drive the drive wheel in rotation along the parts to be welded. During the movement of the welding machine, a current is supplied to the welding wheel by means of a current unit, ensuring the welding of the parts to be welded. Current welders also include a number of components that ensure operation of the welder, such as transformers necessary to perform the weld at least through the welding wheel.

During operation of the welding machine, the welding wheel and other parts of the machine, such as the transformer, are heated, in particular under the effect of the current passing through them. Therefore, the welding machine generally comprises cooling means to ensure cooling of at least the welding wheel and the transformer. Such cooling means make it possible to circulate the heat transfer fluid as much as possible close to the welding wheel and the transformer, notably in order to limit their heating during use.

However, one problem with current cooling devices is particularly related to the fact that they require a large amount of heat transfer fluid to ensure minimum cooling of the different heating components of the welder. Furthermore, the overall cooling performance of the present cooling device can be improved. In fact, current cooling devices propose a conventional circulation of the heat transfer fluid inside the welder, which does not allow the cooling of the welder to be optimized.

It is therefore an object of the present invention to propose a welder whose cooling device can improve the cooling of its components by optimizing the use of a heat transfer fluid. Therefore, a welding machine is proposed which is more economical to use and whose cooling performance is improved.

The invention therefore relates to a welding machine for welding at least two parts to be welded, comprising at least one mobile assembly comprising: at least one pair of drive wheels for moving the moving assembly relative to the part to be welded; at least one welding head comprising at least two welding wheels capable of producing a weld intended to fix a part to be welded by rolling of the welding wheels against the part to be welded; and at least one converter providing a welding current to the welding head, the welding machine comprising a cooling device for cooling the moving assembly, the cooling device comprising at least one cooling circuit extending through the moving assembly and in which a heat transfer fluid circulates, the cooling circuit comprising at least one common conduit from which a first branch and a second branch extend in parallel to each other, the first branch extending through the welding wheel of the welding head, the second branch passing through the converter.

The welding machine according to the invention can be used to weld two raised edges together and/or with anchoring wings of a sealing film constituting the wall of a tank for storing and/or transporting cryogenic products such as liquefied natural gas.

To this end, the welding machine comprises at least one pair of driving wheels which, by means of a driving member, move the moving assembly along the part to be welded in a linear welding direction (also called the advancing direction of the welding machine). The drive member may be, for example, an electric, hydraulic, pneumatic or even a mechanical drive member. Preferably, the drive member in the context of the present invention is an electric motor.

The welding wheel may produce a weld, which may be at least one of a raised edge or an anchor flange, by contact with at least one part to be welded. More specifically, and according to a non-limiting example of the invention, when welding a part to be welded, movement of the welder relative to the part to be welded causes the welding wheel to rotate against the part to be welded, and the current supplied by the power supply unit and passing through the welding wheel makes it possible to form a weld on the part to be welded. It should also be appreciated that the power supply unit makes it possible to supply electric current to the driving members of the driving wheels such that the driving wheels are driven in rotation.

In order to limit the heating of the moving components of the welding machine during use, i.e. during welding of the parts to be welded, the welding machine comprises cooling means. The cooling device according to the invention thus makes it possible to cool the welding wheel on the one hand and the converter on the other hand by means of the first and second branches, respectively, of the cooling circuit through which the heat transfer fluid flows. It will be appreciated that the cooling of the welding wheel and the converter is performed in parallel, thus allowing the latter to be cooled by a heat transfer fluid having the same temperature. Thus, the use of the heat transfer fluid is optimized by optimizing the circulation of the heat transfer fluid in the moving assembly such that at least the converter and the welding wheel are properly cooled without the need for additional heat transfer fluid.

According to one feature of the invention, the mobile assembly comprises at least one transformer through which the common conduit of the cooling circuit passes.

The transformer of the moving assembly corresponds to the element between the welding wheel and the converter, which must be cooled to the greatest extent by the heat transfer fluid. It is therefore an advantage of the present invention to allow the heat transfer fluid to initially cool the transformer, then the heat transfer fluid has its lowest temperature, and then subsequently cool the converter and the welding wheel, which requires that the heat transfer fluid temperature is not so low, using the heat transfer fluid at the outlet of the common conduit. This optimizes the circulation of the heat transfer fluid according to the cooling requirements of each of the transformer, the converter and the welding wheel, which do not require the same temperature of the heat transfer fluid.

According to one feature of the invention, each of the first and second branches comprises an inlet and an outlet in the flow direction of the heat transfer fluid in a cooling circuit comprising at least one intermediate conduit in fluid communication with the outlet of at least the first branch.

It should also be appreciated that the inlet of each of the first and second branches is in fluid communication with the outlet of the common conduit.

According to one feature of the invention, the welding machine comprises a carriage remote from the mobile assembly and connected thereto by means of a wire harness, the carriage comprising at least one tank of heat transfer fluid, a pump and a refrigeration unit comprising a heat exchanger which makes it possible to extract heat from the heat transfer fluid by means of a working fluid circulating in the refrigeration unit.

The cradle further includes a power supply unit of the welder. It should also be appreciated that the heat exchanger cools the heat transfer fluid in the tank so that it has a sufficient temperature at the tank outlet.

According to one feature of the invention, the harness comprises at least one inlet duct connected to the cooling circuit of the mobile assembly, the inlet duct being in fluid communication with the inlet of the common duct, and an outlet duct in fluid communication with at least the outlet of the second branch. Preferably, the outlet conduit is also connected to an intermediate conduit receiving the heat transfer fluid flowing out of the outlet of the first branch.

It will also be appreciated that both the inlet and outlet conduits are connected to the tank of the cooling device, carried by the carriage.

According to one feature of the invention, the welding machine comprises a control unit capable of receiving values of at least one parameter associated with the cooling device, the control unit being configured to control the cooling device in accordance with said at least one parameter.

According to one example of the invention, the parameter related to the cooling device is the temperature of the heat transfer fluid in the tank of the cooling device.

The control device according to the invention may be carried by a carriage or a moving assembly. According to a preferred embodiment of the invention, the control unit is carried by a moving assembly of the welding machine. More specifically, the control unit and the transducer are carried by the same printed circuit board arranged on the mobile assembly.

According to one feature of the invention, the welding machine comprises at least one determining means for determining the temperature of the heat transfer fluid in the tank of the cooling device.

Thus, according to one example of the invention, the determining means is mounted in a tank and makes it possible to detect the temperature value of the heat transfer fluid in said tank.

According to a feature of the invention, the control unit is capable of controlling, at least in part, the operation of the converter.

According to a feature of the invention, the control unit is able to receive the value of at least one parameter associated with the converter in order to control it.

According to one example of the invention, the control unit is able to receive at least one parameter value associated with the transformer for controlling the operation of the welding machine, in particular the operation of the power supply unit of the welding machine, for controlling the power supply of at least the driving members of the welding wheel and the driving wheel in accordance with said parameter value associated with the transformer.

According to one example of the invention, the parameter related to the transformer and/or the converter is their temperature. Thus, control of the transformer and/or the converter is understood to mean controlling at least their temperature. In a complementary manner, the control unit may also control the current generated by the transformer and/or the converter, i.e. the intensity of the welding current.

According to a feature of the invention, the welding machine comprises at least a first sensor detecting a temperature value of the transformer and/or a second sensor detecting a temperature value of the converter, the control unit being configured to control the transformer and/or the converter based on the temperature value detected by the first sensor and/or the second sensor.

It should be appreciated that the control means may control the power supply to at least the drive members of the welding wheel and the drive wheel based on the temperature value detected by the first sensor. In other words, the control unit stops welding of the parts to be welded and advancement of the moving components of the welding machine along the parts to be welded based on the temperature value of the transformer detected by the first sensor.

According to one feature of the invention, the cooling means are configured to ensure a flow rate of the heat transfer fluid in the common conduit at least equal to 6 liters/min. This value is only an example and depends inter alia on the type of transformer used and its power.

It will be appreciated that the pump of the cooling device may be provided at the tank outlet, thereby providing a flow rate of the heat transfer fluid in the common conduit of at least 6L/min.

The invention also relates to a welding control method for controlling the welding of at least two parts to be welded by a welding machine according to any of the preceding features, the welding control method comprising at least:

a step of receiving, by the control unit, at least one temperature value associated with the cooling device;

comparing at least one received temperature value with a reference threshold value of said parameter related to the cooling device;

a step of controlling the cooling device by comparing said at least one received temperature value with a reference threshold value of said parameter.

According to one aspect, when the received temperature value is equal to or greater than the reference threshold, control of the cooling device includes operating it to cool the moving component.

According to another aspect, the control of the cooling means may comprise switching it off when said received temperature value is below said reference threshold value.

It should be appreciated that prior to the receiving step, the control method may comprise the step of inputting at least a reference threshold value related to the temperature of the cooling device in a control interface connected to the control unit. The control interface is carried, for example, by the welder carriage and transmits at least one reference threshold value to the control unit, causing the control unit to perform the comparing step.

The reference threshold refers to the maximum value of the parameter.

Furthermore, the control step makes it possible to cool the heat transfer fluid in the tank by means of a heat exchanger. In other words, the control unit effects cooling of the heat transfer fluid circulating in the mobile assembly by means of the heat exchanger of the refrigeration unit carried by the carriage when the temperature value detected by the determining means and received by the control unit is equal to or greater than a reference threshold value of said parameter.

According to a feature of the invention, the control unit receives at least one parameter value associated with the transformer and/or the converter during the receiving step, then during the comparing step the control unit compares the received at least one value with a reference threshold value of the at least one parameter, and then in the control step the control unit controls the operation of the transformer and/or the converter depending on the comparison of the received value of the parameter with the reference threshold value. In other words, the control unit controls at least the temperature of the converter during the control step.

According to one example of the invention, the control unit receives at least one parameter value related to the transformer during the receiving step, then during the comparing step the control unit compares the at least one received value with a reference threshold value of the at least one parameter, and then in the control step the control unit controls the power supply unit, which supplies current to at least the driving members of the welding wheel and the driving wheel, in dependence of the comparison of the received value of the parameter with the reference threshold value. It will thus be appreciated that the control unit stops the power supply of at least the mobile component as a function of the temperature value detected by the first sensor and related to the temperature of the transformer, related to its associated reference threshold.

It will be appreciated that the step of inputting may comprise inputting at least one reference threshold value of a parameter related to the transformer and/or the converter in the control interface prior to the step of receiving. In the example of the invention, the reference threshold corresponds to a temperature value that is not exceeded, for example 30 ℃.

It is further understood that during the control step, the control unit causes the cooling device to operate to cool the converter when at least one received temperature value of a parameter associated with the converter is equal to or greater than a reference threshold value of said parameter. This control can thus avoid overheating of the converter during use of the welder.

Furthermore, it should be understood that during the control step carried out by the control unit, when at least one of the received temperature values of the parameters related to the transformer is equal to or greater than a reference threshold value of said parameters, the control unit stops at least the power supply of the driving members of the welding wheel and of the driving wheel, so that at least overheating of the transformer, and more generally of the moving assembly, can be avoided.

According to a feature of the invention, the control method operates continuously between a starting position of the mobile assembly and an arrival position of the mobile assembly. The reached position corresponds to a position where the moving assembly interrupts its movement on the part to be welded.

Drawings

Other features, details and advantages of the invention will become apparent from the following description, when read in conjunction with the accompanying drawings, in which:

FIG. 1 is a general perspective view of a tank for storing and/or transporting cryogenic products, the tank comprising at least two parts to be welded that make up a sealing membrane of the tank;

FIG. 2 is a perspective view of a welder according to the present invention capable of welding the two weld parts of FIG. 1;

FIG. 3 is a perspective view of the welder of FIG. 2 showing a cooling device according to the present invention;

fig. 4 is a flow chart of the steps of a method for controlling welding of parts to be welded by a welder according to the present invention.

Detailed Description

It should be noted at the outset that although the drawings illustrate in detail the practice of the invention, these drawings may, of course, be used to better define the invention (as applicable). It should also be noted that these figures illustrate only exemplary embodiments of the invention. Finally, like reference numerals refer to like elements throughout the several views.

Fig. 2 and 3 show a welder 1 configured to move along at least two parts 2 to be welded. More specifically, the parts 2 to be welded constitute a sealing membrane 4 of a wall 6 of a tank 8 for storing and/or transporting cryogenic products (for example liquefied natural gas), and are visible in fig. 1.

The welder 1 comprises at least one moving assembly 10, which is substantially parallelepiped in shape and extends along a main extension direction P parallel to the longitudinal direction L of the welder 1. The moving assembly 10 of the welding machine 1 is intended to move along the part 2 to be welded and for this purpose comprises at least one pair of driving wheels 12, the driving wheels 12 being intended to move the welding machine 1 relative to the part to be welded. More specifically, the driving wheels 12 are arranged in contact with the parts 2 to be welded by means of a pressing device 13 (e.g. a hydraulic cylinder), and the driving members (not visible) make it possible to drive them in rotation against the parts 2 to be welded, so as to move the moving assembly 10 of the welding machine 1. The drive member may be, for example, an electric, hydraulic, pneumatic or even a mechanical drive member. Preferably, the drive member in the context of the present invention is an electric motor. According to the illustrated example of the invention, the moving assembly 10 of the welding machine 1 comprises two pairs of driving wheels 12, which pairs of driving wheels 12 are arranged opposite each other in the main extension direction P of the moving assembly 10.

The mobile assembly 10 further comprises a welding head 14, the welding head 14 comprising at least two welding wheels 16, the welding wheels 16 being able to produce a weld for fixing the parts to be welded by rolling said welding wheels 16 against the parts to be welded. In the illustrated example of the invention, the welding head 14 is arranged between two pairs of driving wheels 12 in the main extension direction P of the moving assembly 10. The welding head 14 further comprises at least one pressurizing device 15 for pressurizing the welding wheel 16 against the part 2 to be welded, the pressurizing device 15 being able to take the form of, for example, a hydraulic cylinder.

In accordance with the present invention, the mobile assembly 10 further includes at least one electrical transducer 18, hereinafter referred to as a transducer, for providing welding current to the welding head 14. In other words, the converter 18 makes it possible to convert the alternating current supplied by the power supply unit 20 of the welding machine 1 so as to be supplied at least to the welding wheel 16, and the converter 18 makes it possible to convert the 50Hz alternating current of the power supply unit 20 into the 1000Hz alternating current required by the welding wheel 16. The converter comprises in particular at least one rectifier bridge, a capacitor and an inverter. The current at the converter output is directed to a transformer/rectifier that converts the 1000Hz ac current into a pulsed current that is sent to the welding wheel 16.

Again in accordance with the present invention, the mobile assembly 10 includes at least one transformer 22 for receiving and converting high voltage and low intensity current at the output of the converter 18 into low voltage and high intensity current for supply to at least the welding wheel 16.

As can be seen from the above, the current at the output of the power supply unit 20 is pre-led to the converter 18 to change from a 50HZ ac current to a 1000HZ ac current, and then to the transformer 22 to reduce its voltage and increase its strength.

The welder 1 further comprises at least one cooling device 24 of the moving assembly 10. More specifically, the cooling device 24 includes a cooling circuit 26, as shown in fig. 3, the cooling circuit 26 circulating the heat transfer fluid as close as possible to the welding wheel 16, the cooling device 24 further including a heat transfer fluid tank 28, a pump 30, and a refrigeration unit 32, the refrigeration unit 32 including at least one heat exchanger 33. Such a cooling device 24 makes it possible in particular to avoid overheating of at least the welding wheel 16 during operation of the welding machine 1. The cooling device 24 will be described in detail later in the description.

The welder 1 further comprises a bracket 34 visible in fig. 2 and 3, remote from the mobile assembly 10, and connected thereto by a wire harness 36. The wiring harness 36 includes, among other things, the electrical and hydraulic connections required to operate the mobile assembly 10. The carrier 34 is particularly configured to carry the components of the welder 1, such as the power supply unit 20 of the welder 1 described above, or the tank 28, pump 30, and refrigeration unit 32 of the cooling device 24.

The function of the power supply unit 20 is to deliver electric current at least to the driving members of the driving wheels 12, thereby driving the driving wheels 12 to rotate to move the moving assembly 10 of the welding machine 1; and supplies current to the welding wheel 16 through the aforementioned converter 18 and transformer 22 so that the welding wheel 16 can weld the parts 2 to be welded when current flows through the welding wheel 16.

The cooling device 24 according to the invention, as can be seen in particular in fig. 3, comprises at least one inlet duct 38 and an outlet duct 40 extending in the wire harness 36 for fluidly connecting the cooling fluid tank 28 to the cooling circuit 26, through which cooling circuit 26 the heat transfer fluid flows, the cooling circuit 26 extending into the moving assembly 10 of the welding machine 1. It should also be appreciated that the pump 30 of the cooling device 24 allows for distribution of the heat transfer fluid into the inlet and outlet conduits 38, 40 and the cooling circuit 26. The refrigeration unit 32 also allows the heat transfer fluid in the tank 28 to be cooled by heat exchange between the heat transfer fluid and the working fluid within the heat exchanger 33. According to one example of the invention, the temperature of the heat transfer fluid in tank 28 is between 20 ℃ and 30 ℃.

The cooling circuit 26 passes through the moving assembly 10, the heat transfer fluid being circulated in the cooling circuit 26, the cooling circuit 26 comprising, inter alia, a common conduit 42, at least one first branch 44 and a second branch 46 extending from the common conduit 42 in parallel with each other. It will thus be appreciated that the first and second branches 44, 46 are fluidly connected to the common conduit 42. As shown in fig. 3, the common conduit 42 passes at least through the transformer 22 such that the heat transfer fluid it carries cools the transformer. Furthermore, according to the invention, the first branch 44 passes at least through the welding wheel 16 of the welding head 14 and the second branch 46 passes at least through the converter 18. It should therefore be appreciated that the heat transfer fluid is intended to cool the transformer 22 first, and then cool the converter 18 and the welding wheel 16 in parallel at the outlet of the common conduit 42.

According to one feature of the invention, the cooling device 24 is configured to provide a flow rate in the common conduit of at least 6 liters/minute. In other words, the pump 30 of the cooling device 24 is configured to provide a flow rate of at least 6L/min to the heat transfer fluid at the outlet of the tank.

The cooling circuit 26 further comprises an intermediate conduit 48 for a heat transfer fluid. More precisely, the inlet 50a,50b and the outlet 52a,52b of each of the first branch 44 and the second branch 46 are fluidly connected to at least the outlet 52a of the first branch 44, depending on the flow direction of the heat transfer fluid in the cooling circuit 26. Furthermore, the outlet 52b of the second branch 46 is directly connected to the above-mentioned outlet duct 40. It should also be appreciated that the inlet 50a,50b of each of the first and second branches 44, 46 is connected to the outlet 52c of the common conduit 42.

As shown in fig. 3, the inlet conduit 38 of the cooling device 24 is in fluid communication with the tank 28 on the one hand, and with the inlet 50c of the common conduit 42 on the other hand, the outlet conduit 40 is in fluid communication with the outlet 52d of the intermediate conduit 48 at the outlet 52b of the second branch 46 of the cooling circuit 26 and with the tank 28.

From the above it follows that the heat transfer fluid at the tank outlet 28, which is at a temperature between 20 and 30 c, first passes through the transformer 22, absorbs heat at the transformer 22 to cool the transformer, so that the heat transfer fluid at the transformer outlet 22 is at a temperature between 20 and 60 c, and is then led in parallel to the welding wheel 16 and the converter 18 to cool them. Thus, the use of the heat transfer fluid may be optimized by pre-directing the heat transfer fluid to the transformer 22, the transformer 22 requiring a lower cooling temperature than the welding wheel 16 and the converter 18.

According to a feature of the invention, the welding machine 1 comprises at least one control unit 54, as shown in fig. 2, capable of receiving values of at least one parameter associated with the cooling device 24, the control unit 54 being configured to control the cooling device 24 at least on the basis of said parameter. The term "control" means that the control unit 54 is able to process the values received from at least one parameter associated with the cooling device 24, in particular by comparing these values with a reference threshold value of said parameter. According to the invention, the reference threshold value may correspond to a maximum value of the parameter.

The control unit 54 here is carried by the moving assembly 10 of the welding machine 1. According to a specific example of the invention, the control unit 54 and the transducer 18 are carried by the same printed circuit board arranged on the mobile assembly 10.

According to the invention, the parameter associated with the cooling device 24 comprises at least one temperature of the heat transfer fluid in the tank 28 of the cooling device 24. Thus, the welding machine 1 comprises at least one determining means 56 for determining the value of the temperature of the heat transfer fluid in the tank 28 of the cooling device 24, the determining means 56 being arranged in said tank 28. According to one example of the invention, the determining means 56 is a sensor comprising at least one temperature sensor.

According to another aspect of the invention, the control unit 54 is capable of controlling, at least in part, the operation of the power supply unit 20 and/or the converter 18, see fig. 3. In other words, the control unit 54 is able to receive values of at least one parameter related to the transformer 22 and/or the converter 18 in order to control the power supply of at least the driving members of the welding wheel and the driving wheel, respectively, and/or to control the converter. Control is understood here to mean that the control unit is able to authorize and/or stop the supply and/or cooling of the converter 18 based on a value received from at least one parameter associated with said value.

Thus, as shown in fig. 3, the welding machine 1 comprises at least a first sensor 58a detecting the temperature value of the transformer 22 and/or a second sensor 58b detecting the temperature value of the converter 18, said temperature values being sent to the control unit for processing thereof. In particular, the control unit receives the temperature values detected by the first sensor 58a and/or the second sensor 58b and compares them with reference values of said parameters in order to control them as described above.

According to one example of the invention, the control unit stops the power supply of the power supply unit 20 to at least the driving members of the welding wheel 16 and the driving wheel 12 when the value received from the parameter related to the transformer 22 is greater than the reference value of said parameter.

A method of controlling welding of parts to be welded will now be described with reference to fig. 2 to 4.

The welding method comprises at least one input step 100 during which a reference threshold input of at least one parameter of the cooling device 24 is connected to the control interface 60 of the control unit 54. In the example of the invention, the parameter of the cooling device 24 corresponds to the temperature of the heat transfer fluid inside the tank 28, and the associated reference threshold value can then be a temperature value or a range of temperature values. According to one example of the invention, the reference threshold for the parameter of the cooling device 24, here the temperature of the heat transfer fluid in the tank 28, is 30 ℃. The inputting step 100 may also include inputting reference values for parameters associated with the transformer 22 and/or the converter 18 as described above. According to an example of the invention, the parameters related to the transformer 22 and/or the converter 18 correspond to their temperature values, and thus their associated reference thresholds correspond to temperature values. For example, the reference threshold associated with the transformer is 80 ℃ and the reference threshold associated with the converter is 100 ℃.

In order to input the at least one reference threshold value and/or the value of the reference threshold value, the welding machine 1 comprises a control interface 60 carried by the carriage 34, in which an operator can perform an input step 100. It should then be appreciated that the control interface 60 is configured to communicate with the control unit 54 carried by the mobile component 10 in order to provide the value of the at least one reference threshold value and/or the reference threshold value thereto.

Subsequently, the control method comprises a step 200 of receiving by the control unit 54 at least one temperature value associated with the cooling device 24. More specifically, during this step, the control unit 54 receives at least one temperature value of the heat transfer fluid contained in the tank 28 and detected by the aforementioned determination means 56. Furthermore, during the receiving step, the control unit 54 may also receive at least one value of one of the parameters related to the transformer 22 and/or the converter 18. In other words, the control unit 54 receives at least one temperature value detected by the first sensor 58a and/or the second sensor 58b in relation to the transformer 22 and/or the converter 18.

Once the receiving step 200 has been performed, the method performs step 300 of comparing at least one temperature value received by the control unit 54 in relation to the cooling device 24 with a reference threshold value of said parameter. Similarly, the comparing step 300 may include comparing, by the control unit 54, the received at least one temperature value with respect to the transformer 22 and/or the converter 18 to an associated reference threshold.

It will be appreciated that as long as the temperature value is below the reference threshold value, the pump will circulate the heat transfer fluid in the cooling circuit, which may be maintained at a temperature below the threshold value by heat exchange with the air surrounding the inlet and outlet conduits 38, 40 and/or due to the tank 28 having a large quantity of heat transfer fluid, which may delay the operation of the refrigeration unit 32.

Finally, once the comparison step 300 has been performed, the control unit 54 performs at least a step 400 of controlling the cooling device 24 by comparing the received temperature value with a reference threshold value. More specifically, when the received temperature value regarding the temperature of the heat transfer fluid in the tank 28 is equal to or greater than the reference threshold value, the control unit 54 starts the operation of the refrigeration unit 32 including the heat exchanger 33, so that the refrigeration unit 32 cools the heat transfer fluid by absorbing heat of the heat transfer fluid via the working fluid circulating in the refrigeration unit 32.

Similarly, at the end of the comparison step 300, the control unit 54 may control the operation of the converter 18 according to the received temperature value during the control step 400. More specifically, when the temperature value received by the control unit 54 with respect to the converter 18 is equal to or greater than its associated reference threshold, the control unit 54 operates the cooling device, and more specifically, the refrigeration unit, so as to cool the converter 18. Thus, putting it into operation in particular makes it possible to avoid overheating of these components and, ultimately, premature wear of them and of the welder 1.

Furthermore, at the end of the comparison step 300, the control unit 54 may control the operation of the power supply unit 20 during the control step 400, i.e. at least stop the power supply of the driving means of the welding wheel 16 and the driving wheel 12 when the temperature value received by the control unit 54 in relation to the transformer 22 is equal to or greater than its relevant reference threshold value.

At the end of the control step 400, the control unit 54 repeats the control method at least at the beginning of the receiving step 200 or the inputting step 100, if a new threshold or reference value has to be entered.

It should also be appreciated that when the comparison step 300 ends with a heat transfer fluid temperature value below the reference threshold, the control unit 54 again performs the receiving step without going through the control step 400. Similarly, when the comparison step 300 ends when the temperature value of the transformer and/or the converter is below the reference threshold value, the control unit 54 returns to the receiving step 200 without executing the control step 400.

It will thus be appreciated that the control method is carried out continuously between the starting position of the mobile assembly 10 and the arrival position of said mobile assembly 10 of the welding machine 1 with respect to the parts to be welded.

Furthermore, it should be considered that the function of the control unit 54 according to the invention is not limited to the function just described, and that the control unit 54 may control other parameters of the cooling device 24 and the converter 18. The described function of the control unit 54 is a non-limiting example of the invention.

The invention just described, however, is not limited to the devices and arrangements specifically described and illustrated, but is also applicable to all equivalent devices or arrangements and any combination of such devices or arrangements.

Claims

1. A welder (1) for welding at least two parts (2) to be welded, the welder (1) comprising at least one moving assembly (10) comprising: -at least one pair of driving wheels (12) for moving the moving assembly (10) with respect to the parts to be welded (2); -at least one welding head (14) comprising at least two welding wheels (16) capable of producing a weld for fixing the part (2) to be welded by rolling of the welding wheels (16) against the part (2) to be welded; the moving assembly (10) comprises at least one converter (18) providing a welding current to the welding head (14), the welding machine (1) comprising cooling means (24) for the moving assembly (10), the cooling means (24) comprising at least one cooling circuit (26) through the moving assembly (10) in which a heat transfer fluid circulates, the cooling circuit (26) comprising at least one common conduit (42) from which at least one first branch (44) and one second branch (46) extend in parallel to each other, the first branch (44) passing through a welding wheel (16) of the welding head (14), the second branch (46) passing through the converter (18).

2. The welding machine (1) according to claim 1, wherein the moving assembly (10) comprises at least one transformer (22), the common conduit (42) of the cooling circuit (26) passing at least through the transformer (22).

3. The welding machine (1) according to claim 1 or 2, wherein each of the first branch (44) and the second branch (46) comprises an inlet (50 a,50 b) and an outlet (52 a,52 b) along a flow direction of coolant in the cooling circuit (26), the cooling circuit (26) comprising at least one intermediate conduit (48), the intermediate conduit (48) being fluidly connected at least to the outlet (52 a) of the first branch (44).

4. The welding machine (1) according to any one of the preceding claims, comprising a cradle (34) remote from the moving assembly (10) and connected to the moving assembly (10) by a wire harness (36), the cradle (34) comprising at least one heat transfer fluid tank (28), a pump (30) and a refrigeration unit (32) comprising a heat exchanger (33) allowing heat to be captured from the heat transfer fluid via a working fluid circulating in the refrigeration unit (32).

5. The welding machine (1) according to any one of the preceding claims, comprising a control unit (54) capable of receiving a value of at least one parameter related to the cooling device (24), the control unit (54) being configured to control the cooling device (24) at least in dependence of the parameter.

6. Welding machine (1) according to claim 5, comprising at least one determining means (56) for determining the temperature of the heat transfer fluid in the tank (28) of the cooling device (24).

7. The welding machine (1) according to claim 5 or 6, wherein the control unit (54) is capable of controlling, at least in part, the operation of the converter (18).

8. The welding machine (1) according to claim 7 in combination with claim 2, comprising at least one first sensor (58 a) detecting a temperature value of the transformer (22) and/or a second sensor (58 b) detecting a temperature value of the converter (18), the control unit (54) being configured to control the transformer (22) and/or the converter (18) based on the temperature value detected by the first sensor (58 a) and/or the second sensor (58 b).

9. The welding machine (1) according to any one of the preceding claims, wherein the cooling device (24) is configured such that the flow rate of the heat transfer fluid within the common conduit is at least equal to 6L/min.

10. A control method for controlling welding of at least two parts (2) by a welding machine (1) according to any one of the preceding claims in combination with any one of the claims 5 to 9, the control method comprising at least:

a receiving step (200) of receiving, by the control unit (54), at least one temperature value associated with the cooling device (24);

a comparison step (300) of comparing the received at least one temperature value with a reference threshold value for the parameter of the cooling device (24);

-a control step (400) of controlling said cooling means (24) by comparing the at least one received temperature value with a reference threshold value of said parameter.

11. The control method according to claim 10 in combination with claim 8, wherein during the receiving step (200) the control unit (54) receives at least one value of a parameter related to the transformer (22) and/or the converter (18), and then during the comparing step (300) the control unit (54) compares the at least one received value with a reference threshold value of the at least one parameter, and then during the controlling step (400) the control unit (54) controls the operation of the transformer (22) and/or the converter (18) based on the comparison of the received value of the parameter with the reference threshold value.

12. The control method according to claim 10 or 11, wherein the control method is continuously performed between a starting position of the moving assembly (10) and an arrival position of the moving assembly (10).