L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des

L'air Liquide

Gerard Marhic

Francis Remy

Didier Schaff

Eric Dufour

Claude Carsac

Georges Duboz

Jean-Pierre Larue

Joel Messager

The plasma welding or cutting system comprises in particular a torch (2), a nozzle (3), a gas supply for the torch for supplying the torch with a plasma-producing gas, and an electrical supply for the torch for creating, maintaining or breaking an electric plasma welding or cutting arc. According to the invention, the system further comprises a delay system connected, on one hand, to the electrical supply for the torch, and, on the other hand, to the gas supply for the torch, the delay system being, when the torch is supplied by the gas supply and the electrical supply, responsive to the breaking of the electric arc of the torch and causing the closure of the gas supply after a predetermined period of time following the breaking of the electric arc so as to achieve the cooling of the torch and the maintenance of the nozzle against its seat during said period of time.

Plasma welding or cutting system provided with a delay

The plasma welding or cutting torch comprises a hollow torch body (1) whose interior is connected to a source of plasma-producing gas, an electrode (2) disposed inside the body (1) and electrically connected to an electrical supply conductor, and a nozzle (3) provided with a plasma outlet orifice (34). This torch is characterized in that it comprises a cartridge (60) which cannot be disassembled and comprises an annular skirt (4) assembled by screwing with the torch body (1) and having a seat (18b) for the nozzle (3) which is freely slidably mounted in the skirt (4) and applied against the seat (18b) solely by the pressure of the plasma-producing gas.

Plasma welding or cutting torch provided with a nozzle cartridge

For forming the plasma arc there is used nitrogen protoxide in the liquid state which is conducted through a valve (12) to an expansion orifice (33) which produces a cooling effect on the electrode (5,6). Applications in particular in plasma arc torch cutting.

Plasma arc forming process and device

This invention relates to plasma torches in which, the gas entering the electrode holder is divided into a plasmagenic gas flow and into a cooling gas flow by two series of openings drilled in one and the same metal element forming the electrode holder.

Plasma torches

There is proposed as a plasma-producing gas, a gas containing the elements nitrogen and oxygen chemically combined in a nitrogen oxide and in particular nitrous oxide. These plasma-producing gases or mixture of gases stored in a bottle, a frame, a container, a tank, in the gaseous or liquid form at ambient or cryogenic temperature, are applicable to the plasma arc cutting of electrically conductive materials.

Gas and process for plasma arc cutting

The arc is struck by the initial short circuit between the electrode (2), the nozzle (3) and the work piece (7) by the excitation by a very low voltage source (31) of a relay (48) causing (between 43 and 42) the closure of the main contact (15), after which the relay (48) is maintained in its state by the welding or cutting current generating a voltage at the terminals of the inductance (23). Application in the control of a torch which is ignited by a short circuit between the electrode, nozzle and the torch.

Very low power plasma arc cutting equipment

The plasma torch comprises a hollow torch body whose interior is connected to a source of plasma-producing gas, a hollow electrode lodged inside this body and electrically connected to an electric supply conductor, and a nozzle provided with an orifice for the outlet of the plasma. The feature of the invention is that the torch comprises a detachable annular skirt (4) which is assembled by a screwed connection with the torch body (1) and has two axially spaced-apart seats (17c,18b) respectively for the electrode (2) and the nozzle (3), and the electrode and the nozzle are freely slidably mounted in the skirt (4) and applied against their respective seats (17c,18b) solely under the action of the pressure of the plasma-producing gas.

Plasma welding or cutting torch

The invention relates in particular to plasma cutting. The nozzle (5) is freely slidably mounted in the torch body so as to come into contact with the electrode if the torch is applied against the work piece (16). By disengaging the torch, an arc is struck between the electrode and the nozzle and then transferred to the work piece. Application in particular to low-power plasma torches.

Arc-striking method for a welding or cutting torch and a torch adapted

This invention relates to arc working torches. To prevent the operator from touching the live electrode, the free end of the torch is provided with a cowling formed by a protective skirt on the one hand and on the other hand by a tilting stirrup hinged on this skirt which engages on the torch body while closing an electrical circuit forming part of the safety circuit of the torch. The invention is applied to manual plasma cutting torches.

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Cergy, France

Gerard Marhic