Patent EP-2366485-B1 (EP)
Inventor: SZCZESNY MICHAEL
IPC: B23K9/167
Filed: 2010-03-17
Granted: 2013-12-25
Abstract: The tungsten-inert gas arc welding device comprises a burner head (2), at whose lower side a tungsten electrode (3) is arranged, where the tungsten electrode has a tip area conically tapering itself to a workpiece (1), a coolant circuit already laying a coolant for impinging the burner head, an energy source (5) having a control unit (6) for electrical power supply of the welding- or soldering process, and a controllable metering unit provided in the cooling circuit for the coolant. The metering unit is controllable by the control unit. The tungsten-inert gas arc welding device comprises a burner head (2), at whose lower side a tungsten electrode (3) is arranged, where the tungsten electrode has a tip area conically tapering itself to a workpiece (1), a coolant circuit already laying a coolant for impinging the burner head, an energy source (5) having a control unit (6) for electrical power supply of the welding- or soldering process, and a controllable metering unit provided in the cooling circuit for the coolant. The metering unit is controllable by the control unit, so that the heat flow from a tungsten electrode body to the burner head is reducible within a predetermined time interval above a switch-off time point of the arc due to a reduction of the coolant quantity and below a switch-on time point of the arc due to a raise of the coolant quantity. A timer is arranged to the control unit, so that the predetermined time interval is defined by a time window, which is formed in the area around the switch-off time point or switch-on time point of the welding current, where the width of the time window is determined by the value of the lead-time and down time. The length of the lead-time and/or length of the down time are proportional to the amplitude of the welding current. The control unit has further timer, by which the welding current is controllable, so that the welding current is switchable again at a further predetermined time after switching the arc and reducing the coolant quantity. The burner head consists of a housing cylinder with an upper lid closure, through which a feed line and a return line for the coolant and a process gas line and an electrical connector are guided for the operation of the tungsten electrode. The burner head has an elongated cooling body present inside the housing cylinder and an elongated opened cavity present in it at the upper front side of the cooling body, and guides an inner lid closure present in it through the lines for the coolant. The burner head has a threaded bore embedded on the lower front side of the cooling body along the burner head axis, where the tungsten electrode is screwable into the threaded bore. The burner head has a screwable gas nozzle connected with the elongated cooling body by involving the longitudinal channels, where the gas nozzle surrounds the cooling body and the tungsten electrode. The tungsten electrode has a cylindrical area in its upper section turned towards the burner head with a thread adapted to the threaded bore. The electrode is joined together with an electrode holder having a passage. The cylindrical area of the electrode is adaptively fixed in the electrode holder using soldering or pressing. The electrode holder has an external thread adapted to the threaded bore for holdably screwing into the threaded hole. The cooling within the cooling body is formed as liquid cooling. The longitudinal channels aligned in axial direction to the burner head axis are present between the elongated cooling body and the gas nozzle and are mounted on the outer wall of the cooling body and/or on the inner wall of the gas nozzle. Independent claims are included for: (1) a burner for an arc welding device; and (2) a method for operating a tungsten-inert gas arc welding device.