Welding nozzle obstruction detection device

Abstract

The invention relates to a device for detecting obstruction of a welding nozzle, the device comprising a fluid source and a welding nozzle fluidically connected by a fluid circuit, and the fluid circuit comprising at least one valve, a flow regulator, a pressure sensor, a control system, and an electrical link connecting the pressure sensor and the control system. The electrical link is configured to transmit to the control system at least one pressure value measured by the pressure sensor, and the control system is configured to compare the measured pressure with a threshold pressure value in order to generate an alert signal when the measured pressure value exceeds the threshold pressure value. (Short figure: Fig. 1)

Description

Title of the invention: Device for detecting the obstruction of a welding nozzle

[0001] The present invention relates to a device for detecting the obstruction of a welding nozzle, for example the obstruction of the nozzle by the adhesion of molten metal projection during the implementation of a welding process.

[0002] The MAG or MIG arc welding process (acronym for "Metal Inert Gas" or "Metal Active Gas" in English) is a welding process that uses an electric arc to achieve the fusion of a base metal with a filler metal. This process uses a consumable electrode that acts as the filler metal, typically a fusible wire whose end is gradually melted by the electric arc. This process can be implemented manually or automatically, that is to say by an automatic machine or a robotic installation. The filler metal as well as the weld pool are protected by the use of an inert welding gas (for example argon or helium) or an active gas (such as oxygen, hydrogen, carbon dioxide).

[0003] In MAG or MIG welding, however, there is a major problem, namely that of the projections which are generated during welding. These projections are accumulated inside the welding nozzle and prevent the gas shielding from being effective. These projections thus compromise the quality of the welding, defects can appear in the weld. In addition, these projections will require finishing work in order to remove these projections. This post-welding work is expensive and difficult to implement, which degrades the productivity of the welding process.

[0004] Application FR2956827A1 discloses a device for preventing the adhesion of projections during arc welding. This device comprises a source of carrier gas, a source of a liquid anti-adhesive product and a gas / liquid mixture spraying system. This device makes it possible to create a protective film against projections of molten metal and thus prevent the welding nozzle from being blocked.

[0005] This type of device is restrictive to implement, because it requires equipping the welding installation with a source of non-stick product in addition to the gas source. In addition, this device requires a significant modification of the welding installation, in particular by adding the spraying system.

[0006] The present invention aims to effectively remedy these drawbacks by proposing a device for detecting the obstruction of a welding nozzle which is simple to implement.

[0007] The invention thus makes it possible to detect the obstruction of the welding nozzle so that the user can act on the nozzle, for example by means of a finishing operation consisting of cleaning the welding nozzle.

[0008] The invention thus relates to a device for detecting the obstruction of a welding nozzle, said device comprising a fluid source, a welding nozzle and a fluid circuit fluidly connecting said fluid source and said welding nozzle, said fluid circuit comprising: - at least one valve capable of authorizing or preventing the distribution of fluid from said fluid source, - a flow regulator capable of regulating the flow rate of said fluid in said fluid circuit, - a pressure sensor capable of measuring the pressure in said fluid circuit, - a control-command system, - an electrical connection means electrically connecting said pressure sensor and said control system, said electrical connection means being configured to transmit to said control system at least one pressure value measured by the pressure sensor, - said control-command system being configured to compare said measured pressure value with a threshold pressure value and to produce an alert signal when said measured pressure value is greater than said threshold pressure value.

[0009] The invention will be better understood thanks to the description which follows, given for illustrative purposes but in no way limiting and made with reference to the attached figure:

[0010] [Fig-1] is a schematic representation of an embodiment of a device according to the invention;

[0011] With reference to [Fig.l], the device 1 for detecting the obstruction of a welding nozzle comprises a fluid source 2. The fluid source 2 is for example a gas cylinder under pressure between 20 and 300 bar. The fluid is for example carbon dioxide, nitrogen or a mixture of these two gases. The detection device 1 comprises a welding nozzle 7. The welding nozzle 7 makes it possible to diffuse the protective gas around the weld bead produced on a substrate 10.

[0012] The welding nozzle 7 and the fluid source 2 are fluidically connected by a fluid circuit. The fluid circuit comprises at least one valve 3. This valve 3 makes it possible to authorize or prevent the flow of fluid from the fluid source. The valve 3 is for example a valve for closing the fluid source, for example an opening / closing tap for a pressurized gas cylinder.

[0013] The fluid circuit comprises a flow regulator 5. The flow regulator makes it possible to regulate the flow rate of said fluid, for example the flow rate is typically between 10 and 20 liters / minute during the MIG / MAG welding operation.

[0014] The fluid circuit comprises a pressure sensor 6. The pressure sensor 6 is capable of measuring the pressure in the fluid circuit. In one embodiment, the pressure sensor can be positioned between the flow regulator 5 and the welding nozzle 7. More particularly, the pressure sensor can be positioned by a tapping on the fluid circuit, for example on a pipe 4 of the fluid circuit. In one embodiment, the pressure sensor 6 is arranged in one embodiment as close as possible to the welding nozzle 7, for example upstream of the torch. When the welding nozzle 7 is obstructed, and when the fluid flow rate is constant, that is to say set to a value by the flow regulator 5, then the pressure in the fluid circuit will increase. The pressure sensor 6, thus positioned, can measure the pressure variation as close as possible to the obstruction of the welding nozzle 7.

[0015] The fluid circuit comprises a control-command system 9 and an electrical connection means 8 electrically connecting the pressure sensor 6 and the control-command system 9. The electrical connection means 8 may be a wired electrical connection means, such as an electric cable or a wireless electrical connection means, such as a Bluetooth connection. The electrical connection means 8 is configured to transmit to the control system 9 at least one pressure value measured by the pressure sensor 6. For example, during the welding operation the electrical connection means 8 transmits a pressure value to the control-command system 9 every second.

[0016] The control-command system 9 is configured to compare the pressure measured by the pressure sensor 6 with a threshold pressure value. When the measured pressure value is greater than the threshold pressure value, the control-command system 9 produces an alert signal. The alert signal may be, for example, a sound emitted or a message displayed on a screen.

[0017] During the welding operation on a substrate 10, projections of material will gradually obstruct the welding nozzle 7. The flow regulator 6 regulates the flow rate of the fluid; if the nozzle is partially obstructed, the pressure in the fluid circuit will increase, the flow rate being constant. The detection device 1 thus makes it possible to detect even partial obstruction of the welding nozzle 7. Indeed, the increase in the measured pressure is an indication of the beginning of obstruction of the welding nozzle 7. In one embodiment of the invention, the pressure sensor 6 is a digital pressure sensor. Thus, pressure variations of a few millibars can be detected.

[0018] The alert signal allows the user to be alerted that a maintenance or completion operation is necessary. When the pressure sensor 6 can measure pressure variations of a few millibars, then the user is warned even if the obstruction of the nozzle is minimal, i.e. without impact consequent on the quality of the weld. Thus the user can carry out a maintenance or finishing operation which at this stage will be less difficult.

[0019] In one embodiment, the control-command system 9 can be electrically connected to a machine configured to clean the automatic nozzle when the pressure measured by the pressure sensor 6 is greater than a threshold value.

[0020] The nozzle obstruction detection device 1 can also be used to detect the obstruction of a nozzle used in a WAAM additive manufacturing process (acronym for “Wire Arc Additive Manufacturing” in English) or in a laser welding process.

Claims

[Claim 1] Claims Device (1) for detecting the obstruction of a welding nozzle, said device comprising a fluid source (2), a welding nozzle (7) and a fluid circuit fluidly connecting said fluid source (2) and said welding nozzle (7), said fluid circuit comprising: - at least one valve (3) capable of authorizing or preventing the distribution of fluid from said fluid source (2), - a flow regulator (5) capable of regulating the flow rate of said fluid in said fluid circuit, - a pressure sensor (6) capable of measuring the pressure in said fluid circuit, - a control-command system (9), - an electrical connection means (8) electrically connecting said pressure sensor (6) and said control-command system (9), said electrical connection means (8) being configured to transmit to said control system (9) at least one pressure value measured by the pressure sensor (6), - said control-command system (9) being configured to compare said measured pressure value with a threshold pressure value and to produce an alert signal when said measured pressure value is greater than said threshold pressure value.

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